[add] i18n support zh,en

api/app/controllers/__init__.py

@@ -16,6 +16,7 @@ from . import (
     file_controller,
     file_storage_controller,
     home_page_controller,
+    i18n_controller,
     implicit_memory_controller,
     knowledge_controller,
     knowledgeshare_controller,
@@ -94,5 +95,6 @@ manager_router.include_router(memory_working_controller.router)
 manager_router.include_router(file_storage_controller.router)
 manager_router.include_router(ontology_controller.router)
 manager_router.include_router(skill_controller.router)
+manager_router.include_router(i18n_controller.router)
 
 __all__ = ["manager_router"]

api/app/controllers/auth_controller.py

@@ -1,4 +1,5 @@
 from datetime import datetime, timedelta, timezone
+from typing import Callable
 from fastapi import APIRouter, Depends
 from sqlalchemy.orm import Session
 
@@ -16,6 +17,7 @@ from app.core.exceptions import BusinessException
 from app.core.error_codes import BizCode
 from app.dependencies import get_current_user, oauth2_scheme
 from app.models.user_model import User
+from app.i18n.dependencies import get_translator
 
 # 获取专用日志器
 auth_logger = get_auth_logger()
@@ -26,7 +28,8 @@ router = APIRouter(tags=["Authentication"])
 @router.post("/token", response_model=ApiResponse)
 async def login_for_access_token(
     form_data: TokenRequest,
-    db: Session = Depends(get_db)
+    db: Session = Depends(get_db),
+    t: Callable = Depends(get_translator)
 ):
     """用户登录获取token"""
     auth_logger.info(f"用户登录请求: {form_data.email}")
@@ -40,10 +43,10 @@ async def login_for_access_token(
         invite_info = workspace_service.validate_invite_token(db, form_data.invite)
         
         if not invite_info.is_valid:
-            raise BusinessException("邀请码无效或已过期", code=BizCode.BAD_REQUEST)
+            raise BusinessException(t("auth.invite.invalid"), code=BizCode.BAD_REQUEST)
         
         if invite_info.email != form_data.email:
-            raise BusinessException("邀请邮箱与登录邮箱不匹配", code=BizCode.BAD_REQUEST)        
+            raise BusinessException(t("auth.invite.email_mismatch"), code=BizCode.BAD_REQUEST)        
         auth_logger.info(f"邀请码验证成功: workspace={invite_info.workspace_name}")
         try:
             # 尝试认证用户
@@ -69,7 +72,7 @@ async def login_for_access_token(
             elif e.code == BizCode.PASSWORD_ERROR:
                 # 用户存在但密码错误
                 auth_logger.warning(f"接受邀请失败，密码验证错误: {form_data.email}")
-                raise BusinessException("接受邀请失败，密码验证错误", BizCode.LOGIN_FAILED)
+                raise BusinessException(t("auth.invite.password_verification_failed"), BizCode.LOGIN_FAILED)
             else:
                 # 其他认证失败情况，直接抛出
                 raise
@@ -82,7 +85,7 @@ async def login_for_access_token(
         except BusinessException as e:
             
             # 其他认证失败情况，直接抛出
-            raise BusinessException(e.message,BizCode.LOGIN_FAILED)
+            raise BusinessException(e.message, BizCode.LOGIN_FAILED)
 
     # 创建 tokens
     access_token, access_token_id = security.create_access_token(subject=user.id)
@@ -110,14 +113,15 @@ async def login_for_access_token(
             expires_at=access_expires_at,
             refresh_expires_at=refresh_expires_at
         ),
-        msg="登录成功"
+        msg=t("auth.login.success")
     )
 
 
 @router.post("/refresh", response_model=ApiResponse)
 async def refresh_token(
     refresh_request: RefreshTokenRequest,
-    db: Session = Depends(get_db)
+    db: Session = Depends(get_db),
+    t: Callable = Depends(get_translator)
 ):
     """刷新token"""
     auth_logger.info("收到token刷新请求")
@@ -125,18 +129,18 @@ async def refresh_token(
     # 验证 refresh token
     userId = security.verify_token(refresh_request.refresh_token, "refresh")
     if not userId:
-        raise BusinessException("无效的refresh token", code=BizCode.TOKEN_INVALID)
+        raise BusinessException(t("auth.token.invalid_refresh_token"), code=BizCode.TOKEN_INVALID)
     
     # 检查用户是否存在
     user = auth_service.get_user_by_id(db, userId)
     if not user:
-        raise BusinessException("用户不存在", code=BizCode.USER_NOT_FOUND)
+        raise BusinessException(t("auth.user.not_found"), code=BizCode.USER_NOT_FOUND)
     
     # 检查 refresh token 黑名单
     if settings.ENABLE_SINGLE_SESSION:
         refresh_token_id = security.get_token_id(refresh_request.refresh_token)
         if refresh_token_id and await SessionService.is_token_blacklisted(refresh_token_id):
-            raise BusinessException("Refresh token已失效", code=BizCode.TOKEN_BLACKLISTED)
+            raise BusinessException(t("auth.token.refresh_token_blacklisted"), code=BizCode.TOKEN_BLACKLISTED)
     
     # 生成新 tokens
     new_access_token, new_access_token_id = security.create_access_token(subject=user.id)
@@ -167,7 +171,7 @@ async def refresh_token(
             expires_at=access_expires_at,
             refresh_expires_at=refresh_expires_at
         ),
-        msg="token刷新成功"
+        msg=t("auth.token.refresh_success")
     )
 
 
@@ -175,14 +179,15 @@ async def refresh_token(
 async def logout(
     token: str = Depends(oauth2_scheme),
     current_user: User = Depends(get_current_user),
-    db: Session = Depends(get_db)
+    db: Session = Depends(get_db),
+    t: Callable = Depends(get_translator)
 ):
     """登出当前用户：加入token黑名单并清理会话"""
     auth_logger.info(f"用户 {current_user.username} 请求登出")
     
     token_id = security.get_token_id(token)
     if not token_id:
-        raise BusinessException("无效的access token", code=BizCode.TOKEN_INVALID)
+        raise BusinessException(t("auth.token.invalid"), code=BizCode.TOKEN_INVALID)
 
     # 加入黑名单
     await SessionService.blacklist_token(token_id)
@@ -192,5 +197,5 @@ async def logout(
         await SessionService.clear_user_session(current_user.username)
 
     auth_logger.info(f"用户 {current_user.username} 登出成功")
-    return success(msg="登出成功")
+    return success(msg=t("auth.logout.success"))
 

api/app/controllers/i18n_controller.py

@@ -0,0 +1,833 @@
+"""
+I18n Management API Controller
+
+This module provides management APIs for:
+- Language management (list, get, add, update languages)
+- Translation management (get, update, reload translations)
+"""
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+from typing import Callable, Optional
+
+from app.core.logging_config import get_api_logger
+from app.core.response_utils import success
+from app.db import get_db
+from app.dependencies import get_current_user, get_current_superuser
+from app.i18n.dependencies import get_translator
+from app.i18n.service import get_translation_service
+from app.models.user_model import User
+from app.schemas.i18n_schema import (
+    LanguageInfo,
+    LanguageListResponse,
+    LanguageCreateRequest,
+    LanguageUpdateRequest,
+    TranslationResponse,
+    TranslationUpdateRequest,
+    MissingTranslationsResponse,
+    ReloadResponse
+)
+from app.schemas.response_schema import ApiResponse
+
+api_logger = get_api_logger()
+
+router = APIRouter(
+    prefix="/i18n",
+    tags=["I18n Management"],
+)
+
+
+# ============================================================================
+# Language Management APIs
+# ============================================================================
+
+@router.get("/languages", response_model=ApiResponse)
+def get_languages(
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_user)
+):
+    """
+    Get list of all supported languages.
+    
+    Returns:
+        List of language information including code, name, and status
+    """
+    api_logger.info(f"Get languages request from user: {current_user.username}")
+    
+    from app.core.config import settings
+    translation_service = get_translation_service()
+    
+    # Get available locales from translation service
+    available_locales = translation_service.get_available_locales()
+    
+    # Build language info list
+    languages = []
+    for locale in available_locales:
+        is_default = locale == settings.I18N_DEFAULT_LANGUAGE
+        is_enabled = locale in settings.I18N_SUPPORTED_LANGUAGES
+        
+        # Get native names
+        native_names = {
+            "zh": "中文（简体）",
+            "en": "English",
+            "ja": "日本語",
+            "ko": "한국어",
+            "fr": "Français",
+            "de": "Deutsch",
+            "es": "Español"
+        }
+        
+        language_info = LanguageInfo(
+            code=locale,
+            name=f"{locale.upper()}",
+            native_name=native_names.get(locale, locale),
+            is_enabled=is_enabled,
+            is_default=is_default
+        )
+        languages.append(language_info)
+    
+    response = LanguageListResponse(languages=languages)
+    
+    api_logger.info(f"Returning {len(languages)} languages")
+    return success(data=response.dict(), msg=t("common.success.retrieved"))
+
+
+@router.get("/languages/{locale}", response_model=ApiResponse)
+def get_language(
+    locale: str,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_user)
+):
+    """
+    Get information about a specific language.
+    
+    Args:
+        locale: Language code (e.g., 'zh', 'en')
+        
+    Returns:
+        Language information
+    """
+    api_logger.info(f"Get language info request: locale={locale}, user={current_user.username}")
+    
+    from app.core.config import settings
+    translation_service = get_translation_service()
+    
+    # Check if locale exists
+    available_locales = translation_service.get_available_locales()
+    if locale not in available_locales:
+        api_logger.warning(f"Language not found: {locale}")
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=t("i18n.language.not_found", locale=locale)
+        )
+    
+    # Build language info
+    is_default = locale == settings.I18N_DEFAULT_LANGUAGE
+    is_enabled = locale in settings.I18N_SUPPORTED_LANGUAGES
+    
+    native_names = {
+        "zh": "中文（简体）",
+        "en": "English",
+        "ja": "日本語",
+        "ko": "한국어",
+        "fr": "Français",
+        "de": "Deutsch",
+        "es": "Español"
+    }
+    
+    language_info = LanguageInfo(
+        code=locale,
+        name=f"{locale.upper()}",
+        native_name=native_names.get(locale, locale),
+        is_enabled=is_enabled,
+        is_default=is_default
+    )
+    
+    api_logger.info(f"Returning language info for: {locale}")
+    return success(data=language_info.dict(), msg=t("common.success.retrieved"))
+
+
+@router.post("/languages", response_model=ApiResponse)
+def add_language(
+    request: LanguageCreateRequest,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Add a new language (admin only).
+    
+    Note: This endpoint validates the request but actual language addition
+    requires creating translation files in the locales directory.
+    
+    Args:
+        request: Language creation request
+        
+    Returns:
+        Success message
+    """
+    api_logger.info(
+        f"Add language request: code={request.code}, admin={current_user.username}"
+    )
+    
+    from app.core.config import settings
+    translation_service = get_translation_service()
+    
+    # Check if language already exists
+    available_locales = translation_service.get_available_locales()
+    if request.code in available_locales:
+        api_logger.warning(f"Language already exists: {request.code}")
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=t("i18n.language.already_exists", locale=request.code)
+        )
+    
+    # Note: Actual language addition requires creating translation files
+    # This endpoint serves as a validation and documentation point
+    
+    api_logger.info(
+        f"Language addition validated: {request.code}. "
+        "Translation files need to be created manually."
+    )
+    
+    return success(
+        msg=t(
+            "i18n.language.add_instructions",
+            locale=request.code,
+            dir=settings.I18N_CORE_LOCALES_DIR
+        )
+    )
+
+
+@router.put("/languages/{locale}", response_model=ApiResponse)
+def update_language(
+    locale: str,
+    request: LanguageUpdateRequest,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Update language configuration (admin only).
+    
+    Note: This endpoint validates the request but actual configuration
+    changes require updating environment variables or config files.
+    
+    Args:
+        locale: Language code
+        request: Language update request
+        
+    Returns:
+        Success message
+    """
+    api_logger.info(
+        f"Update language request: locale={locale}, admin={current_user.username}"
+    )
+    
+    translation_service = get_translation_service()
+    
+    # Check if language exists
+    available_locales = translation_service.get_available_locales()
+    if locale not in available_locales:
+        api_logger.warning(f"Language not found: {locale}")
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=t("i18n.language.not_found", locale=locale)
+        )
+    
+    # Note: Actual configuration changes require updating settings
+    # This endpoint serves as a validation and documentation point
+    
+    api_logger.info(
+        f"Language update validated: {locale}. "
+        "Configuration changes require environment variable updates."
+    )
+    
+    return success(msg=t("i18n.language.update_instructions", locale=locale))
+
+
+# ============================================================================
+# Translation Management APIs
+# ============================================================================
+
+@router.get("/translations", response_model=ApiResponse)
+def get_all_translations(
+    locale: Optional[str] = None,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_user)
+):
+    """
+    Get all translations for all or specific locale.
+    
+    Args:
+        locale: Optional locale filter
+        
+    Returns:
+        All translations organized by locale and namespace
+    """
+    api_logger.info(
+        f"Get all translations request: locale={locale}, user={current_user.username}"
+    )
+    
+    translation_service = get_translation_service()
+    
+    if locale:
+        # Get translations for specific locale
+        available_locales = translation_service.get_available_locales()
+        if locale not in available_locales:
+            raise HTTPException(
+                status_code=status.HTTP_404_NOT_FOUND,
+                detail=t("i18n.language.not_found", locale=locale)
+            )
+        
+        translations = {
+            locale: translation_service._cache.get(locale, {})
+        }
+    else:
+        # Get all translations
+        translations = translation_service._cache
+    
+    response = TranslationResponse(translations=translations)
+    
+    api_logger.info(f"Returning translations for: {locale or 'all locales'}")
+    return success(data=response.dict(), msg=t("common.success.retrieved"))
+
+
+@router.get("/translations/{locale}", response_model=ApiResponse)
+def get_locale_translations(
+    locale: str,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_user)
+):
+    """
+    Get all translations for a specific locale.
+    
+    Args:
+        locale: Language code
+        
+    Returns:
+        All translations for the locale organized by namespace
+    """
+    api_logger.info(
+        f"Get locale translations request: locale={locale}, user={current_user.username}"
+    )
+    
+    translation_service = get_translation_service()
+    
+    # Check if locale exists
+    available_locales = translation_service.get_available_locales()
+    if locale not in available_locales:
+        api_logger.warning(f"Language not found: {locale}")
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=t("i18n.language.not_found", locale=locale)
+        )
+    
+    translations = translation_service._cache.get(locale, {})
+    
+    api_logger.info(f"Returning {len(translations)} namespaces for locale: {locale}")
+    return success(data={"locale": locale, "translations": translations}, msg=t("common.success.retrieved"))
+
+
+@router.get("/translations/{locale}/{namespace}", response_model=ApiResponse)
+def get_namespace_translations(
+    locale: str,
+    namespace: str,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_user)
+):
+    """
+    Get translations for a specific namespace in a locale.
+    
+    Args:
+        locale: Language code
+        namespace: Translation namespace (e.g., 'common', 'auth')
+        
+    Returns:
+        Translations for the specified namespace
+    """
+    api_logger.info(
+        f"Get namespace translations request: locale={locale}, "
+        f"namespace={namespace}, user={current_user.username}"
+    )
+    
+    translation_service = get_translation_service()
+    
+    # Check if locale exists
+    available_locales = translation_service.get_available_locales()
+    if locale not in available_locales:
+        api_logger.warning(f"Language not found: {locale}")
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=t("i18n.language.not_found", locale=locale)
+        )
+    
+    # Get namespace translations
+    locale_translations = translation_service._cache.get(locale, {})
+    namespace_translations = locale_translations.get(namespace, {})
+    
+    if not namespace_translations:
+        api_logger.warning(f"Namespace not found: {namespace} in locale: {locale}")
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=t("i18n.namespace.not_found", namespace=namespace, locale=locale)
+        )
+    
+    api_logger.info(
+        f"Returning translations for namespace: {namespace} in locale: {locale}"
+    )
+    return success(
+        data={
+            "locale": locale,
+            "namespace": namespace,
+            "translations": namespace_translations
+        },
+        msg=t("common.success.retrieved")
+    )
+
+
+@router.put("/translations/{locale}/{key:path}", response_model=ApiResponse)
+def update_translation(
+    locale: str,
+    key: str,
+    request: TranslationUpdateRequest,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Update a single translation (admin only).
+    
+    Note: This endpoint validates the request but actual translation updates
+    require modifying translation files in the locales directory.
+    
+    Args:
+        locale: Language code
+        key: Translation key (format: "namespace.key.subkey")
+        request: Translation update request
+        
+    Returns:
+        Success message
+    """
+    api_logger.info(
+        f"Update translation request: locale={locale}, key={key}, "
+        f"admin={current_user.username}"
+    )
+    
+    translation_service = get_translation_service()
+    
+    # Check if locale exists
+    available_locales = translation_service.get_available_locales()
+    if locale not in available_locales:
+        api_logger.warning(f"Language not found: {locale}")
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=t("i18n.language.not_found", locale=locale)
+        )
+    
+    # Validate key format
+    if "." not in key:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=t("i18n.translation.invalid_key_format", key=key)
+        )
+    
+    # Note: Actual translation updates require modifying JSON files
+    # This endpoint serves as a validation and documentation point
+    
+    api_logger.info(
+        f"Translation update validated: {locale}/{key}. "
+        "Translation files need to be updated manually."
+    )
+    
+    return success(
+        msg=t("i18n.translation.update_instructions", locale=locale, key=key)
+    )
+
+
+@router.get("/translations/missing", response_model=ApiResponse)
+def get_missing_translations(
+    locale: Optional[str] = None,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_user)
+):
+    """
+    Get list of missing translations.
+    
+    Compares translations across locales to find missing keys.
+    
+    Args:
+        locale: Optional locale to check (defaults to checking all non-default locales)
+        
+    Returns:
+        List of missing translation keys
+    """
+    api_logger.info(
+        f"Get missing translations request: locale={locale}, user={current_user.username}"
+    )
+    
+    from app.core.config import settings
+    translation_service = get_translation_service()
+    
+    default_locale = settings.I18N_DEFAULT_LANGUAGE
+    available_locales = translation_service.get_available_locales()
+    
+    # Get default locale translations as reference
+    default_translations = translation_service._cache.get(default_locale, {})
+    
+    # Collect all keys from default locale
+    def collect_keys(data, prefix=""):
+        keys = []
+        for key, value in data.items():
+            full_key = f"{prefix}.{key}" if prefix else key
+            if isinstance(value, dict):
+                keys.extend(collect_keys(value, full_key))
+            else:
+                keys.append(full_key)
+        return keys
+    
+    default_keys = set()
+    for namespace, translations in default_translations.items():
+        namespace_keys = collect_keys(translations, namespace)
+        default_keys.update(namespace_keys)
+    
+    # Find missing keys in target locale(s)
+    missing_by_locale = {}
+    
+    target_locales = [locale] if locale else [
+        loc for loc in available_locales if loc != default_locale
+    ]
+    
+    for target_locale in target_locales:
+        if target_locale not in available_locales:
+            continue
+        
+        target_translations = translation_service._cache.get(target_locale, {})
+        target_keys = set()
+        
+        for namespace, translations in target_translations.items():
+            namespace_keys = collect_keys(translations, namespace)
+            target_keys.update(namespace_keys)
+        
+        missing_keys = default_keys - target_keys
+        if missing_keys:
+            missing_by_locale[target_locale] = sorted(list(missing_keys))
+    
+    response = MissingTranslationsResponse(missing_translations=missing_by_locale)
+    
+    total_missing = sum(len(keys) for keys in missing_by_locale.values())
+    api_logger.info(f"Found {total_missing} missing translations across {len(missing_by_locale)} locales")
+    
+    return success(data=response.dict(), msg=t("common.success.retrieved"))
+
+
+@router.post("/reload", response_model=ApiResponse)
+def reload_translations(
+    locale: Optional[str] = None,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Trigger hot reload of translation files (admin only).
+    
+    Args:
+        locale: Optional locale to reload (defaults to reloading all locales)
+        
+    Returns:
+        Reload status and statistics
+    """
+    api_logger.info(
+        f"Reload translations request: locale={locale or 'all'}, "
+        f"admin={current_user.username}"
+    )
+    
+    from app.core.config import settings
+    
+    if not settings.I18N_ENABLE_HOT_RELOAD:
+        api_logger.warning("Hot reload is disabled in configuration")
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail=t("i18n.reload.disabled")
+        )
+    
+    translation_service = get_translation_service()
+    
+    try:
+        # Reload translations
+        translation_service.reload(locale)
+        
+        # Get statistics
+        available_locales = translation_service.get_available_locales()
+        reloaded_locales = [locale] if locale else available_locales
+        
+        response = ReloadResponse(
+            success=True,
+            reloaded_locales=reloaded_locales,
+            total_locales=len(available_locales)
+        )
+        
+        api_logger.info(
+            f"Successfully reloaded translations for: {', '.join(reloaded_locales)}"
+        )
+        
+        return success(data=response.dict(), msg=t("i18n.reload.success"))
+        
+    except Exception as e:
+        api_logger.error(f"Failed to reload translations: {str(e)}")
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=t("i18n.reload.failed", error=str(e))
+        )
+
+
+# ============================================================================
+# Performance Monitoring APIs
+# ============================================================================
+
+@router.get("/metrics", response_model=ApiResponse)
+def get_metrics(
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Get i18n performance metrics (admin only).
+    
+    Returns:
+        Performance metrics including:
+        - Request counts
+        - Missing translations
+        - Timing statistics
+        - Locale usage
+        - Error counts
+    """
+    api_logger.info(f"Get metrics request: admin={current_user.username}")
+    
+    translation_service = get_translation_service()
+    metrics = translation_service.get_metrics_summary()
+    
+    api_logger.info("Returning i18n metrics")
+    return success(data=metrics, msg=t("common.success.retrieved"))
+
+
+@router.get("/metrics/cache", response_model=ApiResponse)
+def get_cache_stats(
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Get cache statistics (admin only).
+    
+    Returns:
+        Cache statistics including:
+        - Hit/miss rates
+        - LRU cache performance
+        - Loaded locales
+        - Memory usage
+    """
+    api_logger.info(f"Get cache stats request: admin={current_user.username}")
+    
+    translation_service = get_translation_service()
+    cache_stats = translation_service.get_cache_stats()
+    memory_usage = translation_service.get_memory_usage()
+    
+    data = {
+        "cache": cache_stats,
+        "memory": memory_usage
+    }
+    
+    api_logger.info("Returning cache statistics")
+    return success(data=data, msg=t("common.success.retrieved"))
+
+
+@router.get("/metrics/prometheus")
+def get_prometheus_metrics(
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Get metrics in Prometheus format (admin only).
+    
+    Returns:
+        Prometheus-formatted metrics as plain text
+    """
+    api_logger.info(f"Get Prometheus metrics request: admin={current_user.username}")
+    
+    from app.i18n.metrics import get_metrics
+    metrics = get_metrics()
+    prometheus_output = metrics.export_prometheus()
+    
+    from fastapi.responses import PlainTextResponse
+    return PlainTextResponse(content=prometheus_output)
+
+
+@router.post("/metrics/reset", response_model=ApiResponse)
+def reset_metrics(
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Reset all metrics (admin only).
+    
+    Returns:
+        Success message
+    """
+    api_logger.info(f"Reset metrics request: admin={current_user.username}")
+    
+    from app.i18n.metrics import get_metrics
+    metrics = get_metrics()
+    metrics.reset()
+    
+    translation_service = get_translation_service()
+    translation_service.cache.reset_stats()
+    
+    api_logger.info("Metrics reset completed")
+    return success(msg=t("i18n.metrics.reset_success"))
+
+
+# ============================================================================
+# Missing Translation Logging and Reporting APIs
+# ============================================================================
+
+@router.get("/logs/missing", response_model=ApiResponse)
+def get_missing_translation_logs(
+    locale: Optional[str] = None,
+    limit: Optional[int] = 100,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Get missing translation logs (admin only).
+    
+    Returns logged missing translations with context information.
+    
+    Args:
+        locale: Optional locale filter
+        limit: Maximum number of entries to return (default: 100)
+        
+    Returns:
+        Missing translation logs with context
+    """
+    api_logger.info(
+        f"Get missing translation logs request: locale={locale}, "
+        f"limit={limit}, admin={current_user.username}"
+    )
+    
+    translation_service = get_translation_service()
+    translation_logger = translation_service.translation_logger
+    
+    # Get missing translations
+    missing_translations = translation_logger.get_missing_translations(locale)
+    
+    # Get missing with context
+    missing_with_context = translation_logger.get_missing_with_context(locale, limit)
+    
+    # Get statistics
+    statistics = translation_logger.get_statistics()
+    
+    data = {
+        "missing_translations": missing_translations,
+        "recent_context": missing_with_context,
+        "statistics": statistics
+    }
+    
+    api_logger.info(
+        f"Returning {statistics['total_missing']} missing translations"
+    )
+    return success(data=data, msg=t("common.success.retrieved"))
+
+
+@router.get("/logs/missing/report", response_model=ApiResponse)
+def generate_missing_translation_report(
+    locale: Optional[str] = None,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Generate a comprehensive missing translation report (admin only).
+    
+    Args:
+        locale: Optional locale filter
+        
+    Returns:
+        Comprehensive report with missing translations and statistics
+    """
+    api_logger.info(
+        f"Generate missing translation report request: locale={locale}, "
+        f"admin={current_user.username}"
+    )
+    
+    translation_service = get_translation_service()
+    translation_logger = translation_service.translation_logger
+    
+    # Generate report
+    report = translation_logger.generate_report(locale)
+    
+    api_logger.info(
+        f"Generated report with {report['total_missing']} missing translations"
+    )
+    return success(data=report, msg=t("common.success.retrieved"))
+
+
+@router.post("/logs/missing/export", response_model=ApiResponse)
+def export_missing_translations(
+    locale: Optional[str] = None,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Export missing translations to JSON file (admin only).
+    
+    Args:
+        locale: Optional locale filter
+        
+    Returns:
+        Export status and file path
+    """
+    api_logger.info(
+        f"Export missing translations request: locale={locale}, "
+        f"admin={current_user.username}"
+    )
+    
+    from datetime import datetime
+    translation_service = get_translation_service()
+    translation_logger = translation_service.translation_logger
+    
+    # Generate filename with timestamp
+    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
+    locale_suffix = f"_{locale}" if locale else "_all"
+    output_file = f"logs/i18n/missing_translations{locale_suffix}_{timestamp}.json"
+    
+    # Export to file
+    translation_logger.export_to_json(output_file)
+    
+    api_logger.info(f"Missing translations exported to: {output_file}")
+    return success(
+        data={"file_path": output_file},
+        msg=t("i18n.logs.export_success", file=output_file)
+    )
+
+
+@router.delete("/logs/missing", response_model=ApiResponse)
+def clear_missing_translation_logs(
+    locale: Optional[str] = None,
+    t: Callable = Depends(get_translator),
+    current_user: User = Depends(get_current_superuser)
+):
+    """
+    Clear missing translation logs (admin only).
+    
+    Args:
+        locale: Optional locale to clear (clears all if not specified)
+        
+    Returns:
+        Success message
+    """
+    api_logger.info(
+        f"Clear missing translation logs request: locale={locale or 'all'}, "
+        f"admin={current_user.username}"
+    )
+    
+    translation_service = get_translation_service()
+    translation_logger = translation_service.translation_logger
+    
+    # Clear logs
+    translation_logger.clear(locale)
+    
+    api_logger.info(f"Cleared missing translation logs for: {locale or 'all locales'}")
+    return success(msg=t("i18n.logs.clear_success"))

api/app/controllers/user_controller.py

@@ -1,6 +1,7 @@
 from fastapi import APIRouter, Depends
 from sqlalchemy.orm import Session
 import uuid
+from typing import Callable
 
 from app.core.error_codes import BizCode
 from app.core.exceptions import BusinessException
@@ -19,6 +20,7 @@ from app.services import user_service
 from app.core.logging_config import get_api_logger
 from app.core.response_utils import success
 from app.core.security import verify_password
+from app.i18n.dependencies import get_translator
 
 # 获取API专用日志器
 api_logger = get_api_logger()
@@ -33,7 +35,8 @@ router = APIRouter(
 def create_superuser(
     user: user_schema.UserCreate,
     db: Session = Depends(get_db),
-    current_superuser: User = Depends(get_current_superuser)
+    current_superuser: User = Depends(get_current_superuser),
+    t: Callable = Depends(get_translator)
 ):
     """创建超级管理员（仅超级管理员可访问）"""
     api_logger.info(f"超级管理员创建请求: {user.username}, email: {user.email}")
@@ -42,7 +45,7 @@ def create_superuser(
     api_logger.info(f"超级管理员创建成功: {result.username} (ID: {result.id})")
     
     result_schema = user_schema.User.model_validate(result)
-    return success(data=result_schema, msg="超级管理员创建成功")
+    return success(data=result_schema, msg=t("users.create.superuser_success"))
 
 
 @router.delete("/{user_id}", response_model=ApiResponse)
@@ -50,6 +53,7 @@ def delete_user(
     user_id: uuid.UUID,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
 ):
     """停用用户（软删除）"""
     api_logger.info(f"用户停用请求: user_id={user_id}, 操作者: {current_user.username}")
@@ -57,13 +61,14 @@ def delete_user(
         db=db, user_id_to_deactivate=user_id, current_user=current_user
     )
     api_logger.info(f"用户停用成功: {result.username} (ID: {result.id})")
-    return success(msg="用户停用成功")
+    return success(msg=t("users.delete.deactivate_success"))
 
 @router.post("/{user_id}/activate", response_model=ApiResponse)
 def activate_user(
     user_id: uuid.UUID,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
 ):
     """激活用户"""
     api_logger.info(f"用户激活请求: user_id={user_id}, 操作者: {current_user.username}")
@@ -74,13 +79,14 @@ def activate_user(
     api_logger.info(f"用户激活成功: {result.username} (ID: {result.id})")
     
     result_schema = user_schema.User.model_validate(result)
-    return success(data=result_schema, msg="用户激活成功")
+    return success(data=result_schema, msg=t("users.activate.success"))
 
 
 @router.get("", response_model=ApiResponse)
 def get_current_user_info(
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
 ):
     """获取当前用户信息"""
     api_logger.info(f"当前用户信息请求: {current_user.username}")
@@ -105,7 +111,7 @@ def get_current_user_info(
                 break
     
     api_logger.info(f"当前用户信息获取成功: {result.username}, 角色: {result_schema.role}, 工作空间: {result_schema.current_workspace_name}")
-    return success(data=result_schema, msg="用户信息获取成功")
+    return success(data=result_schema, msg=t("users.info.get_success"))
 
 
 @router.get("/superusers", response_model=ApiResponse)
@@ -113,6 +119,7 @@ def get_tenant_superusers(
     include_inactive: bool = False,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_superuser),
+    t: Callable = Depends(get_translator)
 ):
     """获取当前租户下的超管账号列表（仅超级管理员可访问）"""
     api_logger.info(f"获取租户超管列表请求: {current_user.username}")
@@ -125,7 +132,7 @@ def get_tenant_superusers(
     api_logger.info(f"租户超管列表获取成功: count={len(superusers)}")
     
     superusers_schema = [user_schema.User.model_validate(u) for u in superusers]
-    return success(data=superusers_schema, msg="租户超管列表获取成功")
+    return success(data=superusers_schema, msg=t("users.list.superusers_success"))
 
 
 
@@ -134,6 +141,7 @@ def get_user_info_by_id(
     user_id: uuid.UUID,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
 ):
     """根据用户ID获取用户信息"""
     api_logger.info(f"获取用户信息请求: user_id={user_id}, 操作者: {current_user.username}")
@@ -144,7 +152,7 @@ def get_user_info_by_id(
     api_logger.info(f"用户信息获取成功: {result.username}")
     
     result_schema = user_schema.User.model_validate(result)
-    return success(data=result_schema, msg="用户信息获取成功")
+    return success(data=result_schema, msg=t("users.info.get_success"))
 
 
 @router.put("/change-password", response_model=ApiResponse)
@@ -152,6 +160,7 @@ async def change_password(
     request: ChangePasswordRequest,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
 ):
     """修改当前用户密码"""
     api_logger.info(f"用户密码修改请求: {current_user.username}")
@@ -164,7 +173,7 @@ async def change_password(
         current_user=current_user
     )
     api_logger.info(f"用户密码修改成功: {current_user.username}")
-    return success(msg="密码修改成功")
+    return success(msg=t("auth.password.change_success"))
 
 
 @router.put("/admin/change-password", response_model=ApiResponse)
@@ -172,6 +181,7 @@ async def admin_change_password(
     request: AdminChangePasswordRequest,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_superuser),
+    t: Callable = Depends(get_translator)
 ):
     """超级管理员修改指定用户的密码"""
     api_logger.info(f"管理员密码修改请求: 管理员 {current_user.username} 修改用户 {request.user_id}")
@@ -186,16 +196,17 @@ async def admin_change_password(
     # 根据是否生成了随机密码来构造响应
     if request.new_password:
         api_logger.info(f"管理员密码修改成功: 用户 {request.user_id}")
-        return success(msg="密码修改成功")
+        return success(msg=t("auth.password.change_success"))
     else:
         api_logger.info(f"管理员密码重置成功: 用户 {request.user_id}, 随机密码已生成")
-        return success(data=generated_password, msg="密码重置成功")
+        return success(data=generated_password, msg=t("auth.password.reset_success"))
 
 
 @router.post("/verify_pwd", response_model=ApiResponse)
 def verify_pwd(
     request: VerifyPasswordRequest,
     current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
 ):
     """验证当前用户密码"""
     api_logger.info(f"用户验证密码请求: {current_user.username}")
@@ -203,8 +214,8 @@ def verify_pwd(
     is_valid = verify_password(request.password, current_user.hashed_password)
     api_logger.info(f"用户密码验证结果: {current_user.username}, valid={is_valid}")
     if not is_valid:
-        raise BusinessException("密码验证失败", code=BizCode.VALIDATION_FAILED)
-    return success(data={"valid": is_valid}, msg="验证完成")
+        raise BusinessException(t("users.errors.password_verification_failed"), code=BizCode.VALIDATION_FAILED)
+    return success(data={"valid": is_valid}, msg=t("common.success.retrieved"))
 
 
 @router.post("/send-email-code", response_model=ApiResponse)
@@ -212,6 +223,7 @@ async def send_email_code(
     request: SendEmailCodeRequest,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
 ):
     """发送邮箱验证码"""
     api_logger.info(f"用户请求发送邮箱验证码: {current_user.username}, email={request.email}")
@@ -219,7 +231,7 @@ async def send_email_code(
     await user_service.send_email_code_method(db=db, email=request.email, user_id=current_user.id)
     
     api_logger.info(f"邮箱验证码已发送: {current_user.username}")
-    return success(msg="验证码已发送到您的邮箱，请查收")
+    return success(msg=t("users.email.code_sent"))
 
 
 @router.put("/change-email", response_model=ApiResponse)
@@ -227,6 +239,7 @@ async def change_email(
     request: VerifyEmailCodeRequest,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
 ):
     """验证验证码并修改邮箱"""
     api_logger.info(f"用户修改邮箱: {current_user.username}, new_email={request.new_email}")
@@ -239,4 +252,51 @@ async def change_email(
     )
     
     api_logger.info(f"用户邮箱修改成功: {current_user.username}")
-    return success(msg="邮箱修改成功")
+    return success(msg=t("users.email.change_success"))
+
+
+
+@router.get("/me/language", response_model=ApiResponse)
+def get_current_user_language(
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
+):
+    """获取当前用户的语言偏好"""
+    api_logger.info(f"获取用户语言偏好: {current_user.username}")
+    
+    language = user_service.get_user_language_preference(
+        db=db,
+        user_id=current_user.id,
+        current_user=current_user
+    )
+    
+    api_logger.info(f"用户语言偏好获取成功: {current_user.username}, language={language}")
+    return success(
+        data=user_schema.LanguagePreferenceResponse(language=language),
+        msg=t("users.language.get_success")
+    )
+
+
+@router.put("/me/language", response_model=ApiResponse)
+def update_current_user_language(
+    request: user_schema.LanguagePreferenceRequest,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    t: Callable = Depends(get_translator)
+):
+    """设置当前用户的语言偏好"""
+    api_logger.info(f"更新用户语言偏好: {current_user.username}, language={request.language}")
+    
+    updated_user = user_service.update_user_language_preference(
+        db=db,
+        user_id=current_user.id,
+        language=request.language,
+        current_user=current_user
+    )
+    
+    api_logger.info(f"用户语言偏好更新成功: {current_user.username}, language={request.language}")
+    return success(
+        data=user_schema.LanguagePreferenceResponse(language=updated_user.preferred_language),
+        msg=t("users.language.update_success")
+    )

api/app/controllers/workspace_controller.py

@@ -14,6 +14,12 @@ from app.dependencies import (
     get_current_user,
     workspace_access_guard,
 )
+from app.i18n.dependencies import get_current_language, get_translator
+from app.i18n.serializers import (
+    WorkspaceSerializer,
+    WorkspaceMemberSerializer,
+    WorkspaceInviteSerializer
+)
 from app.models.tenant_model import Tenants
 from app.models.user_model import User
 from app.models.workspace_model import InviteStatus
@@ -65,7 +71,9 @@ def get_workspaces(
     include_current: bool = Query(True, description="是否包含当前工作空间"),
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
-    current_tenant: Tenants = Depends(get_current_tenant)
+    current_tenant: Tenants = Depends(get_current_tenant),
+    language: str = Depends(get_current_language),
+    t: callable = Depends(get_translator)
 ):
     """获取当前租户下用户参与的所有工作空间
 
@@ -88,8 +96,13 @@ def get_workspaces(
         )
 
     api_logger.info(f"成功获取 {len(workspaces)} 个工作空间")
-    workspaces_schema = [WorkspaceResponse.model_validate(w) for w in workspaces]
-    return success(data=workspaces_schema, msg="工作空间列表获取成功")
+    
+    # 使用序列化器添加国际化字段
+    serializer = WorkspaceSerializer()
+    workspaces_data = [WorkspaceResponse.model_validate(w).model_dump() for w in workspaces]
+    workspaces_i18n = serializer.serialize_list(workspaces_data, language)
+    
+    return success(data=workspaces_i18n, msg=t("workspace.list_retrieved"))
 
 
 @router.post("", response_model=ApiResponse)
@@ -98,6 +111,8 @@ def create_workspace(
     language_type: str = Header(default="zh", alias="X-Language-Type"),
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_superuser),
+    language: str = Depends(get_current_language),
+    t: callable = Depends(get_translator)
 ):
     """创建新的工作空间"""
     from app.core.language_utils import get_language_from_header
@@ -118,8 +133,13 @@ def create_workspace(
         f"工作空间创建成功 - 名称: {workspace.name}, ID: {result.id}, "
         f"创建者: {current_user.username}, language={language}"
     )
-    result_schema = WorkspaceResponse.model_validate(result)
-    return success(data=result_schema, msg="工作空间创建成功")
+    
+    # 使用序列化器添加国际化字段
+    serializer = WorkspaceSerializer()
+    result_data = WorkspaceResponse.model_validate(result).model_dump()
+    result_i18n = serializer.serialize(result_data, language)
+    
+    return success(data=result_i18n, msg=t("workspace.created"))
 
 @router.put("", response_model=ApiResponse)
 @cur_workspace_access_guard()
@@ -127,6 +147,8 @@ def update_workspace(
     workspace: WorkspaceUpdate,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    language: str = Depends(get_current_language),
+    t: callable = Depends(get_translator)
 ):
     """更新工作空间"""
     workspace_id = current_user.current_workspace_id
@@ -139,14 +161,21 @@ def update_workspace(
         user=current_user,
     )
     api_logger.info(f"工作空间更新成功 - ID: {workspace_id}, 用户: {current_user.username}")
-    result_schema = WorkspaceResponse.model_validate(result)
-    return success(data=result_schema, msg="工作空间更新成功")
+    
+    # 使用序列化器添加国际化字段
+    serializer = WorkspaceSerializer()
+    result_data = WorkspaceResponse.model_validate(result).model_dump()
+    result_i18n = serializer.serialize(result_data, language)
+    
+    return success(data=result_i18n, msg=t("workspace.updated"))
 
 @router.get("/members", response_model=ApiResponse)
 @cur_workspace_access_guard()
 def get_cur_workspace_members(
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    language: str = Depends(get_current_language),
+    t: callable = Depends(get_translator)
 ):
     """获取工作空间成员列表（关系序列化）"""
     api_logger.info(f"用户 {current_user.username} 请求获取工作空间 {current_user.current_workspace_id} 的成员列表")
@@ -157,8 +186,14 @@ def get_cur_workspace_members(
         user=current_user,
     )
     api_logger.info(f"工作空间成员列表获取成功 - ID: {current_user.current_workspace_id}, 数量: {len(members)}")
+    
+    # 转换为表格项并使用序列化器添加国际化字段
     table_items = _convert_members_to_table_items(members)
-    return success(data=table_items, msg="工作空间成员列表获取成功")
+    serializer = WorkspaceMemberSerializer()
+    members_data = [item.model_dump() for item in table_items]
+    members_i18n = serializer.serialize_list(members_data, language)
+    
+    return success(data=members_i18n, msg=t("workspace.members.list_retrieved"))
 
 
 @router.put("/members", response_model=ApiResponse)
@@ -168,6 +203,7 @@ def update_workspace_members(
     updates: List[WorkspaceMemberUpdate],
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: callable = Depends(get_translator)
 ):
     workspace_id = current_user.current_workspace_id
     api_logger.info(f"用户 {current_user.username} 请求更新工作空间 {workspace_id} 的成员角色")
@@ -178,7 +214,7 @@ def update_workspace_members(
         user=current_user,
     )
     api_logger.info(f"工作空间成员角色更新成功 - ID: {workspace_id}, 数量: {len(members)}")
-    return success(msg="成员角色更新成功")
+    return success(msg=t("workspace.members.role_updated"))
 
 
 @router.delete("/members/{member_id}", response_model=ApiResponse)
@@ -187,6 +223,7 @@ def delete_workspace_member(
     member_id: uuid.UUID,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: callable = Depends(get_translator)
 ):
     workspace_id = current_user.current_workspace_id
     api_logger.info(f"用户 {current_user.username} 请求删除工作空间 {workspace_id} 的成员 {member_id}")
@@ -198,7 +235,7 @@ def delete_workspace_member(
         user=current_user,
     )
     api_logger.info(f"工作空间成员删除成功 - ID: {workspace_id}, 成员: {member_id}")
-    return success(msg="成员删除成功")
+    return success(msg=t("workspace.members.deleted"))
 
 
 # 创建空间协作邀请
@@ -208,6 +245,8 @@ def create_workspace_invite(
     invite_data: WorkspaceInviteCreate,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    language: str = Depends(get_current_language),
+    t: callable = Depends(get_translator)
 ):
     """创建工作空间邀请"""
     workspace_id = current_user.current_workspace_id
@@ -220,7 +259,12 @@ def create_workspace_invite(
         user=current_user
     )
     api_logger.info(f"工作空间邀请创建成功 - 工作空间: {workspace_id}, 邮箱: {invite_data.email}")
-    return success(data=result, msg="邀请创建成功")
+    
+    # 使用序列化器添加国际化字段
+    serializer = WorkspaceInviteSerializer()
+    result_i18n = serializer.serialize(result, language)
+    
+    return success(data=result_i18n, msg=t("workspace.invites.created"))
 
 
 @router.get("/invites", response_model=ApiResponse)
@@ -232,6 +276,8 @@ def get_workspace_invites(
     offset: int = Query(0, ge=0),
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    language: str = Depends(get_current_language),
+    t: callable = Depends(get_translator)
 ):
     """获取工作空间邀请列表"""
     workspace_id = current_user.current_workspace_id
@@ -246,18 +292,30 @@ def get_workspace_invites(
         offset=offset
     )
     api_logger.info(f"成功获取 {len(invites)} 个邀请记录")
-    return success(data=invites, msg="邀请列表获取成功")
+    
+    # 使用序列化器添加国际化字段
+    serializer = WorkspaceInviteSerializer()
+    invites_i18n = serializer.serialize_list(invites, language)
+    
+    return success(data=invites_i18n, msg=t("workspace.invites.list_retrieved"))
 
 
 @public_router.get("/invites/validate/{token}", response_model=ApiResponse)
 def get_workspace_invite_info(
     token: str,
     db: Session = Depends(get_db),
+    language: str = Depends(get_current_language),
+    t: callable = Depends(get_translator)
 ):
     """获取工作空间邀请用户信息（无需认证）"""
     result = workspace_service.validate_invite_token(db=db, token=token)
     api_logger.info(f"工作空间邀请验证成功 - 邀请: {token}")
-    return success(data=result, msg="邀请验证成功")
+    
+    # 使用序列化器添加国际化字段
+    serializer = WorkspaceInviteSerializer()
+    result_i18n = serializer.serialize(result, language)
+    
+    return success(data=result_i18n, msg=t("workspace.invites.validated"))
 
 
 @router.delete("/invites/{invite_id}", response_model=ApiResponse)
@@ -267,6 +325,8 @@ def revoke_workspace_invite(
     invite_id: uuid.UUID,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    language: str = Depends(get_current_language),
+    t: callable = Depends(get_translator)
 ):
     """撤销工作空间邀请"""
     workspace_id = current_user.current_workspace_id
@@ -279,7 +339,12 @@ def revoke_workspace_invite(
         user=current_user
     )
     api_logger.info(f"工作空间邀请撤销成功 - 邀请: {invite_id}")
-    return success(data=result, msg="邀请撤销成功")
+    
+    # 使用序列化器添加国际化字段
+    serializer = WorkspaceInviteSerializer()
+    result_i18n = serializer.serialize(result, language)
+    
+    return success(data=result_i18n, msg=t("workspace.invites.revoked"))
 
 # ==================== 公开邀请接口（无需认证） ====================
 
@@ -302,6 +367,7 @@ def switch_workspace(
     workspace_id: uuid.UUID,
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
+    t: callable = Depends(get_translator)
 ):
     """切换工作空间"""
     api_logger.info(f"用户 {current_user.username} 请求切换工作空间为 {workspace_id}")
@@ -312,7 +378,7 @@ def switch_workspace(
         user=current_user,
     )
     api_logger.info(f"成功切换工作空间为 {workspace_id}")
-    return success(msg="工作空间切换成功")
+    return success(msg=t("workspace.switched"))
 
 
 @router.get("/storage", response_model=ApiResponse)
@@ -320,6 +386,7 @@ def switch_workspace(
 def get_workspace_storage_type(
         db: Session = Depends(get_db),
         current_user: User = Depends(get_current_user),
+        t: callable = Depends(get_translator)
 ):
     """获取当前工作空间的存储类型"""
     workspace_id = current_user.current_workspace_id
@@ -331,7 +398,7 @@ def get_workspace_storage_type(
         user=current_user
     )
     api_logger.info(f"成功获取工作空间 {workspace_id} 的存储类型: {storage_type}")
-    return success(data={"storage_type": storage_type}, msg="存储类型获取成功")
+    return success(data={"storage_type": storage_type}, msg=t("workspace.storage.type_retrieved"))
 
 
 @router.get("/workspace_models", response_model=ApiResponse)
@@ -339,6 +406,8 @@ def get_workspace_storage_type(
 def workspace_models_configs(
         db: Session = Depends(get_db),
         current_user: User = Depends(get_current_user),
+        language: str = Depends(get_current_language),
+        t: callable = Depends(get_translator)
 ):
     """获取当前工作空间的模型配置（llm, embedding, rerank）"""
     workspace_id = current_user.current_workspace_id
@@ -354,14 +423,14 @@ def workspace_models_configs(
         api_logger.warning(f"工作空间 {workspace_id} 不存在或无权访问")
         raise HTTPException(
             status_code=status.HTTP_404_NOT_FOUND,
-            detail="工作空间不存在或无权访问"
+            detail=t("workspace.not_found")
         )
 
     api_logger.info(
         f"成功获取工作空间 {workspace_id} 的模型配置: "
         f"llm={configs.get('llm')}, embedding={configs.get('embedding')}, rerank={configs.get('rerank')}"
     )
-    return success(data=WorkspaceModelsConfig.model_validate(configs), msg="模型配置获取成功")
+    return success(data=WorkspaceModelsConfig.model_validate(configs), msg=t("workspace.models.config_retrieved"))
 
 
 @router.put("/workspace_models", response_model=ApiResponse)
@@ -370,6 +439,7 @@ def update_workspace_models_configs(
         models_update: WorkspaceModelsUpdate,
         db: Session = Depends(get_db),
         current_user: User = Depends(get_current_user),
+        t: callable = Depends(get_translator)
 ):
     """更新当前工作空间的模型配置（llm, embedding, rerank）"""
     workspace_id = current_user.current_workspace_id
@@ -386,5 +456,5 @@ def update_workspace_models_configs(
         f"成功更新工作空间 {workspace_id} 的模型配置: "
         f"llm={updated_workspace.llm}, embedding={updated_workspace.embedding}, rerank={updated_workspace.rerank}"
     )
-    return success(data=WorkspaceModelsConfig.model_validate(updated_workspace), msg="模型配置更新成功")
+    return success(data=WorkspaceModelsConfig.model_validate(updated_workspace), msg=t("workspace.models.config_updated"))
 

api/app/core/config.py

@@ -162,6 +162,44 @@ class Settings:
     # This controls the language used for memory summary titles and other generated content
     DEFAULT_LANGUAGE: str = os.getenv("DEFAULT_LANGUAGE", "zh")
 
+    # ========================================================================
+    # Internationalization (i18n) Configuration
+    # ========================================================================
+    # Default language for API responses
+    I18N_DEFAULT_LANGUAGE: str = os.getenv("I18N_DEFAULT_LANGUAGE", "zh")
+    
+    # Supported languages (comma-separated)
+    I18N_SUPPORTED_LANGUAGES: list[str] = [
+        lang.strip()
+        for lang in os.getenv("I18N_SUPPORTED_LANGUAGES", "zh,en").split(",")
+        if lang.strip()
+    ]
+    
+    # Core locales directory (community edition)
+    # Use absolute path to work from any working directory
+    I18N_CORE_LOCALES_DIR: str = os.getenv(
+        "I18N_CORE_LOCALES_DIR",
+        os.path.join(os.path.dirname(os.path.dirname(__file__)), "locales")
+    )
+    
+    # Premium locales directory (enterprise edition, optional)
+    I18N_PREMIUM_LOCALES_DIR: Optional[str] = os.getenv("I18N_PREMIUM_LOCALES_DIR", None)
+    
+    # Enable translation cache
+    I18N_ENABLE_TRANSLATION_CACHE: bool = os.getenv("I18N_ENABLE_TRANSLATION_CACHE", "true").lower() == "true"
+    
+    # LRU cache size for hot translations
+    I18N_LRU_CACHE_SIZE: int = int(os.getenv("I18N_LRU_CACHE_SIZE", "1000"))
+    
+    # Enable hot reload of translation files
+    I18N_ENABLE_HOT_RELOAD: bool = os.getenv("I18N_ENABLE_HOT_RELOAD", "false").lower() == "true"
+    
+    # Fallback language when translation is missing
+    I18N_FALLBACK_LANGUAGE: str = os.getenv("I18N_FALLBACK_LANGUAGE", "zh")
+    
+    # Log missing translations
+    I18N_LOG_MISSING_TRANSLATIONS: bool = os.getenv("I18N_LOG_MISSING_TRANSLATIONS", "true").lower() == "true"
+
     # Logging settings
     LOG_LEVEL: str = os.getenv("LOG_LEVEL", "INFO")
     LOG_FORMAT: str = os.getenv("LOG_FORMAT", "%(asctime)s - %(name)s - %(levelname)s - %(message)s")

api/app/i18n/README.md

@@ -0,0 +1,61 @@
+# Internationalization (i18n) Module
+
+This module provides internationalization support for the MemoryBear API.
+
+## Components
+
+- `service.py` - Translation service and core translation logic
+- `middleware.py` - Language detection middleware
+- `dependencies.py` - FastAPI dependency injection functions
+- `exceptions.py` - Internationalized exception classes
+
+## Usage
+
+### Basic Translation
+
+```python
+from app.i18n import t
+
+# Simple translation
+message = t("common.success.created")
+
+# Parameterized translation
+message = t("common.validation.required", field="Name")
+```
+
+### Enum Translation
+
+```python
+from app.i18n import t_enum
+
+# Translate enum value
+role_display = t_enum("workspace_role", "manager")
+```
+
+### In FastAPI Endpoints
+
+```python
+from fastapi import Depends
+from app.i18n.dependencies import get_translator
+
+@router.post("/workspaces")
+async def create_workspace(
+    data: WorkspaceCreate,
+    t: Callable = Depends(get_translator)
+):
+    workspace = await workspace_service.create(data)
+    return {
+        "success": True,
+        "message": t("workspace.created_successfully"),
+        "data": workspace
+    }
+```
+
+## Configuration
+
+See `app/core/config.py` for i18n configuration options:
+
+- `I18N_DEFAULT_LANGUAGE` - Default language (default: "zh")
+- `I18N_SUPPORTED_LANGUAGES` - Supported languages (default: "zh,en")
+- `I18N_ENABLE_TRANSLATION_CACHE` - Enable caching (default: true)
+- `I18N_LOG_MISSING_TRANSLATIONS` - Log missing translations (default: true)

api/app/i18n/__init__.py

@@ -0,0 +1,113 @@
+"""
+Internationalization (i18n) module for MemoryBear Enterprise.
+
+This module provides complete i18n support for the backend API including:
+- Translation loading from multiple directories (community + enterprise)
+- Translation service with caching and fallback
+- Language detection middleware
+- Dependency injection for FastAPI
+- Convenience functions for easy usage
+
+Usage:
+    from app.i18n import t, t_enum
+
+    # Simple translation
+    message = t("common.success.created")
+
+    # Parameterized translation
+    error = t("common.validation.required", field="名称")
+
+    # Enum translation
+    role_display = t_enum("workspace_role", "manager")
+"""
+
+from app.i18n.dependencies import (
+    get_current_language,
+    get_enum_translator,
+    get_translator,
+)
+from app.i18n.exceptions import (
+    BadRequestError,
+    ConflictError,
+    FileNotFoundError,
+    FileTooLargeError,
+    ForbiddenError,
+    I18nException,
+    InternalServerError,
+    InvalidCredentialsError,
+    InvalidFileTypeError,
+    NotFoundError,
+    QuotaExceededError,
+    RateLimitExceededError,
+    ServiceUnavailableError,
+    TenantNotFoundError,
+    TenantSuspendedError,
+    TokenExpiredError,
+    TokenInvalidError,
+    UnauthorizedError,
+    UserAlreadyExistsError,
+    UserNotFoundError,
+    ValidationError,
+    WorkspaceNotFoundError,
+    WorkspacePermissionDeniedError,
+    get_current_locale,
+    set_current_locale,
+)
+from app.i18n.loader import TranslationLoader
+from app.i18n.logger import (
+    TranslationLogger,
+    get_translation_logger,
+    log_missing_translation,
+    log_translation_error,
+)
+from app.i18n.middleware import LanguageMiddleware
+from app.i18n.service import (
+    TranslationService,
+    get_translation_service,
+    t,
+    t_enum,
+)
+
+__all__ = [
+    "TranslationLoader",
+    "LanguageMiddleware",
+    "TranslationService",
+    "get_translation_service",
+    "t",
+    "t_enum",
+    "get_current_language",
+    "get_translator",
+    "get_enum_translator",
+    # Context management
+    "get_current_locale",
+    "set_current_locale",
+    # Logging
+    "TranslationLogger",
+    "get_translation_logger",
+    "log_missing_translation",
+    "log_translation_error",
+    # Exception classes
+    "I18nException",
+    "BadRequestError",
+    "UnauthorizedError",
+    "ForbiddenError",
+    "NotFoundError",
+    "ConflictError",
+    "ValidationError",
+    "InternalServerError",
+    "ServiceUnavailableError",
+    "WorkspaceNotFoundError",
+    "WorkspacePermissionDeniedError",
+    "UserNotFoundError",
+    "UserAlreadyExistsError",
+    "TenantNotFoundError",
+    "TenantSuspendedError",
+    "InvalidCredentialsError",
+    "TokenExpiredError",
+    "TokenInvalidError",
+    "FileNotFoundError",
+    "FileTooLargeError",
+    "InvalidFileTypeError",
+    "RateLimitExceededError",
+    "QuotaExceededError",
+]

api/app/i18n/cache.py

@@ -0,0 +1,291 @@
+"""
+Advanced caching system for i18n translations.
+
+This module provides:
+- LRU cache for hot translations
+- Lazy loading mechanism
+- Memory optimization
+- Cache statistics
+"""
+
+import logging
+from functools import lru_cache
+from typing import Any, Dict, Optional
+from collections import OrderedDict
+import time
+
+logger = logging.getLogger(__name__)
+
+
+class TranslationCache:
+    """
+    Advanced translation cache with LRU eviction and lazy loading.
+    
+    Features:
+    - LRU cache for frequently accessed translations
+    - Lazy loading to reduce startup time
+    - Memory-efficient storage
+    - Cache hit/miss statistics
+    """
+    
+    def __init__(self, max_lru_size: int = 1000, enable_lazy_load: bool = True):
+        """
+        Initialize the translation cache.
+        
+        Args:
+            max_lru_size: Maximum size of LRU cache for hot translations
+            enable_lazy_load: Enable lazy loading of locales
+        """
+        self.max_lru_size = max_lru_size
+        self.enable_lazy_load = enable_lazy_load
+        
+        # Main cache: {locale: {namespace: {key: value}}}
+        self._main_cache: Dict[str, Dict[str, Any]] = {}
+        
+        # LRU cache for hot translations
+        self._lru_cache: OrderedDict = OrderedDict()
+        
+        # Loaded locales tracker
+        self._loaded_locales: set = set()
+        
+        # Statistics
+        self._stats = {
+            "hits": 0,
+            "misses": 0,
+            "lru_hits": 0,
+            "lru_misses": 0,
+            "lazy_loads": 0
+        }
+        
+        logger.info(
+            f"TranslationCache initialized with LRU size: {max_lru_size}, "
+            f"lazy loading: {enable_lazy_load}"
+        )
+    
+    def set_locale_data(self, locale: str, data: Dict[str, Any]):
+        """
+        Set translation data for a locale.
+        
+        Args:
+            locale: Locale code
+            data: Translation data dictionary
+        """
+        self._main_cache[locale] = data
+        self._loaded_locales.add(locale)
+        logger.debug(f"Loaded locale '{locale}' into cache")
+    
+    def get_translation(
+        self,
+        locale: str,
+        namespace: str,
+        key_path: list
+    ) -> Optional[str]:
+        """
+        Get translation from cache with LRU optimization.
+        
+        Args:
+            locale: Locale code
+            namespace: Translation namespace
+            key_path: List of nested keys
+            
+        Returns:
+            Translation string or None if not found
+        """
+        # Build cache key for LRU
+        cache_key = f"{locale}:{namespace}:{'.'.join(key_path)}"
+        
+        # Check LRU cache first (hot translations)
+        if cache_key in self._lru_cache:
+            self._stats["lru_hits"] += 1
+            self._stats["hits"] += 1
+            # Move to end (most recently used)
+            self._lru_cache.move_to_end(cache_key)
+            return self._lru_cache[cache_key]
+        
+        self._stats["lru_misses"] += 1
+        
+        # Check main cache
+        if locale not in self._main_cache:
+            self._stats["misses"] += 1
+            return None
+        
+        if namespace not in self._main_cache[locale]:
+            self._stats["misses"] += 1
+            return None
+        
+        # Navigate through nested keys
+        current = self._main_cache[locale][namespace]
+        for key in key_path:
+            if isinstance(current, dict) and key in current:
+                current = current[key]
+            else:
+                self._stats["misses"] += 1
+                return None
+        
+        # Return only if it's a string value
+        if not isinstance(current, str):
+            self._stats["misses"] += 1
+            return None
+        
+        self._stats["hits"] += 1
+        
+        # Add to LRU cache
+        self._add_to_lru(cache_key, current)
+        
+        return current
+    
+    def _add_to_lru(self, key: str, value: str):
+        """
+        Add translation to LRU cache.
+        
+        Args:
+            key: Cache key
+            value: Translation value
+        """
+        # Remove oldest if cache is full
+        if len(self._lru_cache) >= self.max_lru_size:
+            self._lru_cache.popitem(last=False)
+        
+        self._lru_cache[key] = value
+    
+    def is_locale_loaded(self, locale: str) -> bool:
+        """
+        Check if a locale is loaded.
+        
+        Args:
+            locale: Locale code
+            
+        Returns:
+            True if locale is loaded
+        """
+        return locale in self._loaded_locales
+    
+    def get_loaded_locales(self) -> list:
+        """
+        Get list of loaded locales.
+        
+        Returns:
+            List of locale codes
+        """
+        return list(self._loaded_locales)
+    
+    def clear_lru(self):
+        """Clear the LRU cache."""
+        self._lru_cache.clear()
+        logger.info("LRU cache cleared")
+    
+    def clear_locale(self, locale: str):
+        """
+        Clear cache for a specific locale.
+        
+        Args:
+            locale: Locale code
+        """
+        if locale in self._main_cache:
+            del self._main_cache[locale]
+            self._loaded_locales.discard(locale)
+        
+        # Clear related LRU entries
+        keys_to_remove = [k for k in self._lru_cache if k.startswith(f"{locale}:")]
+        for key in keys_to_remove:
+            del self._lru_cache[key]
+        
+        logger.info(f"Cleared cache for locale '{locale}'")
+    
+    def clear_all(self):
+        """Clear all caches."""
+        self._main_cache.clear()
+        self._lru_cache.clear()
+        self._loaded_locales.clear()
+        logger.info("All caches cleared")
+    
+    def get_stats(self) -> Dict[str, Any]:
+        """
+        Get cache statistics.
+        
+        Returns:
+            Dictionary with cache statistics
+        """
+        total_requests = self._stats["hits"] + self._stats["misses"]
+        hit_rate = (
+            self._stats["hits"] / total_requests * 100
+            if total_requests > 0
+            else 0
+        )
+        
+        lru_total = self._stats["lru_hits"] + self._stats["lru_misses"]
+        lru_hit_rate = (
+            self._stats["lru_hits"] / lru_total * 100
+            if lru_total > 0
+            else 0
+        )
+        
+        return {
+            "total_requests": total_requests,
+            "hits": self._stats["hits"],
+            "misses": self._stats["misses"],
+            "hit_rate": round(hit_rate, 2),
+            "lru_hits": self._stats["lru_hits"],
+            "lru_misses": self._stats["lru_misses"],
+            "lru_hit_rate": round(lru_hit_rate, 2),
+            "lru_size": len(self._lru_cache),
+            "lru_max_size": self.max_lru_size,
+            "loaded_locales": len(self._loaded_locales),
+            "lazy_loads": self._stats["lazy_loads"]
+        }
+    
+    def reset_stats(self):
+        """Reset cache statistics."""
+        self._stats = {
+            "hits": 0,
+            "misses": 0,
+            "lru_hits": 0,
+            "lru_misses": 0,
+            "lazy_loads": 0
+        }
+        logger.info("Cache statistics reset")
+    
+    def get_memory_usage(self) -> Dict[str, Any]:
+        """
+        Estimate memory usage of the cache.
+        
+        Returns:
+            Dictionary with memory usage information
+        """
+        import sys
+        
+        main_cache_size = sys.getsizeof(self._main_cache)
+        lru_cache_size = sys.getsizeof(self._lru_cache)
+        
+        # Rough estimate of nested data
+        for locale_data in self._main_cache.values():
+            main_cache_size += sys.getsizeof(locale_data)
+            for namespace_data in locale_data.values():
+                main_cache_size += sys.getsizeof(namespace_data)
+        
+        return {
+            "main_cache_bytes": main_cache_size,
+            "lru_cache_bytes": lru_cache_size,
+            "total_bytes": main_cache_size + lru_cache_size,
+            "main_cache_mb": round(main_cache_size / 1024 / 1024, 2),
+            "lru_cache_mb": round(lru_cache_size / 1024 / 1024, 2),
+            "total_mb": round((main_cache_size + lru_cache_size) / 1024 / 1024, 2)
+        }
+
+
+@lru_cache(maxsize=128)
+def get_cached_translation_key(locale: str, namespace: str, key: str) -> str:
+    """
+    LRU cached function for building translation cache keys.
+    
+    This reduces string concatenation overhead for frequently accessed keys.
+    
+    Args:
+        locale: Locale code
+        namespace: Translation namespace
+        key: Translation key
+        
+    Returns:
+        Cache key string
+    """
+    return f"{locale}:{namespace}:{key}"

api/app/i18n/dependencies.py

@@ -0,0 +1,158 @@
+"""
+FastAPI dependency injection functions for i18n.
+
+This module provides dependency injection functions that can be used
+in FastAPI route handlers to access the current language and translator.
+"""
+
+import logging
+from typing import Callable
+
+from fastapi import Request
+
+from app.i18n.service import get_translation_service
+
+logger = logging.getLogger(__name__)
+
+
+async def get_current_language(request: Request) -> str:
+    """
+    Get the current language from the request context.
+
+    This dependency extracts the language that was determined by the
+    LanguageMiddleware and stored in request.state.
+
+    Args:
+        request: FastAPI request object
+
+    Returns:
+        Language code (e.g., "zh", "en")
+
+    Usage:
+        @router.get("/example")
+        async def example(language: str = Depends(get_current_language)):
+            return {"language": language}
+    """
+    # Get language from request state (set by LanguageMiddleware)
+    language = getattr(request.state, "language", None)
+
+    if language is None:
+        # Fallback to default language if not set
+        from app.core.config import settings
+        language = settings.I18N_DEFAULT_LANGUAGE
+        logger.warning(
+            "Language not found in request.state, using default: "
+            f"{language}"
+        )
+
+    return language
+
+
+async def get_translator(request: Request) -> Callable:
+    """
+    Get a translator function bound to the current request's language.
+
+    This dependency returns a translation function that automatically
+    uses the current request's language, making it easy to translate
+    strings in route handlers.
+
+    Args:
+        request: FastAPI request object
+
+    Returns:
+        Translation function with signature: t(key: str, **params) -> str
+
+    Usage:
+        @router.post("/workspaces")
+        async def create_workspace(
+            data: WorkspaceCreate,
+            t: Callable = Depends(get_translator)
+        ):
+            workspace = await workspace_service.create(data)
+            return {
+                "success": True,
+                "message": t("workspace.created_successfully"),
+                "data": workspace
+            }
+
+        # With parameters
+        @router.get("/items")
+        async def get_items(t: Callable = Depends(get_translator)):
+            count = 5
+            return {
+                "message": t("items.found", count=count)
+            }
+    """
+    # Get current language
+    language = await get_current_language(request)
+
+    # Get translation service
+    service = get_translation_service()
+
+    # Return a bound translation function
+    def translate(key: str, **params) -> str:
+        """
+        Translate a key using the current request's language.
+
+        Args:
+            key: Translation key (e.g., "common.success.created")
+            **params: Parameters for parameterized messages
+
+        Returns:
+            Translated string
+        """
+        return service.translate(key, language, **params)
+
+    return translate
+
+
+async def get_enum_translator(request: Request) -> Callable:
+    """
+    Get an enum translator function bound to the current request's language.
+
+    This dependency returns a function for translating enum values
+    that automatically uses the current request's language.
+
+    Args:
+        request: FastAPI request object
+
+    Returns:
+        Enum translation function with signature:
+        t_enum(enum_type: str, value: str) -> str
+
+    Usage:
+        @router.get("/workspace/{id}")
+        async def get_workspace(
+            id: str,
+            t_enum: Callable = Depends(get_enum_translator)
+        ):
+            workspace = await workspace_service.get(id)
+            return {
+                "id": workspace.id,
+                "role": workspace.role,
+                "role_display": t_enum("workspace_role", workspace.role),
+                "status": workspace.status,
+                "status_display": t_enum("workspace_status", workspace.status)
+            }
+    """
+    # Get current language
+    language = await get_current_language(request)
+
+    # Get translation service
+    service = get_translation_service()
+
+    # Return a bound enum translation function
+    def translate_enum(enum_type: str, value: str) -> str:
+        """
+        Translate an enum value using the current request's language.
+
+        Args:
+            enum_type: Enum type name (e.g., "workspace_role")
+            value: Enum value (e.g., "manager")
+
+        Returns:
+            Translated enum display name
+        """
+        return service.translate_enum(enum_type, value, language)
+
+    return translate_enum

api/app/i18n/exceptions.py

@@ -0,0 +1,495 @@
+"""
+Internationalized exception classes for i18n system.
+
+This module provides exception classes that automatically translate
+error messages based on the current request's language.
+"""
+
+import logging
+from contextvars import ContextVar
+from typing import Any, Dict, Optional
+
+from fastapi import HTTPException, Request
+
+from app.i18n.service import get_translation_service
+
+logger = logging.getLogger(__name__)
+
+# Context variable to store current locale
+_current_locale: ContextVar[Optional[str]] = ContextVar("current_locale", default=None)
+
+
+def set_current_locale(locale: str) -> None:
+    """
+    Set the current locale in the context variable.
+    
+    This should be called by the LanguageMiddleware.
+    
+    Args:
+        locale: Locale code (e.g., "zh", "en")
+    """
+    _current_locale.set(locale)
+
+
+def get_current_locale() -> Optional[str]:
+    """
+    Get the current locale from the context variable.
+    
+    Returns:
+        Locale code or None if not set
+    """
+    return _current_locale.get()
+
+
+class I18nException(HTTPException):
+    """
+    Base exception class with automatic i18n support.
+
+    This exception automatically translates error messages based on:
+    1. The current request's language (from request.state.language)
+    2. The fallback language if request language is not available
+    3. The error key itself if no translation is found
+
+    Features:
+    - Automatic error message translation
+    - Parameterized error messages support
+    - Consistent error response format
+    - Language-aware error handling
+
+    Usage:
+        # Simple error
+        raise I18nException(
+            error_key="errors.workspace.not_found",
+            status_code=404
+        )
+
+        # Error with parameters
+        raise I18nException(
+            error_key="errors.validation.missing_field",
+            status_code=400,
+            field="name"
+        )
+
+        # Custom error code
+        raise I18nException(
+            error_key="errors.workspace.not_found",
+            error_code="WORKSPACE_NOT_FOUND",
+            status_code=404,
+            workspace_id="123"
+        )
+    """
+
+    def __init__(
+        self,
+        error_key: str,
+        status_code: int = 400,
+        error_code: Optional[str] = None,
+        locale: Optional[str] = None,
+        headers: Optional[Dict[str, str]] = None,
+        **params
+    ):
+        """
+        Initialize the i18n exception.
+
+        Args:
+            error_key: Translation key for the error message
+                      (e.g., "errors.workspace.not_found")
+            status_code: HTTP status code (default: 400)
+            error_code: Custom error code for API clients
+                       (default: derived from error_key)
+            locale: Target locale for translation (optional)
+                   If not provided, uses current request's language
+            headers: Additional HTTP headers
+            **params: Parameters for parameterized error messages
+        """
+        self.error_key = error_key
+        self.error_code = error_code or self._generate_error_code(error_key)
+        self.params = params
+
+        # Get locale from request context if not provided
+        if locale is None:
+            locale = self._get_current_locale()
+
+        # Translate error message
+        translation_service = get_translation_service()
+        message = translation_service.translate(
+            error_key,
+            locale,
+            **params
+        )
+
+        # Build error detail
+        detail = {
+            "error_code": self.error_code,
+            "message": message,
+        }
+
+        # Add parameters to detail if provided
+        if params:
+            detail["params"] = params
+
+        # Initialize HTTPException
+        super().__init__(
+            status_code=status_code,
+            detail=detail,
+            headers=headers
+        )
+
+        logger.debug(
+            f"I18nException raised: {self.error_code} "
+            f"(key: {error_key}, locale: {locale})"
+        )
+
+    def _get_current_locale(self) -> str:
+        """
+        Get the current locale from request context.
+
+        Returns:
+            Locale code (e.g., "zh", "en")
+        """
+        try:
+            # Try to get locale from context variable
+            locale = _current_locale.get()
+            if locale:
+                return locale
+        except Exception as e:
+            logger.debug(f"Could not get locale from context: {e}")
+
+        # Fallback to default locale
+        from app.core.config import settings
+        return settings.I18N_DEFAULT_LANGUAGE
+
+    def _generate_error_code(self, error_key: str) -> str:
+        """
+        Generate error code from error key.
+
+        Converts "errors.workspace.not_found" to "WORKSPACE_NOT_FOUND"
+
+        Args:
+            error_key: Translation key
+
+        Returns:
+            Error code in UPPER_SNAKE_CASE
+        """
+        # Remove "errors." prefix if present
+        if error_key.startswith("errors."):
+            error_key = error_key[7:]
+
+        # Convert to UPPER_SNAKE_CASE
+        parts = error_key.split(".")
+        return "_".join(parts).upper()
+
+
+# Specific exception classes for common errors
+
+class BadRequestError(I18nException):
+    """Bad request error (400)."""
+
+    def __init__(
+        self,
+        error_key: str = "errors.common.bad_request",
+        error_code: Optional[str] = None,
+        **params
+    ):
+        super().__init__(
+            error_key=error_key,
+            status_code=400,
+            error_code=error_code,
+            **params
+        )
+
+
+class UnauthorizedError(I18nException):
+    """Unauthorized error (401)."""
+
+    def __init__(
+        self,
+        error_key: str = "errors.auth.unauthorized",
+        error_code: Optional[str] = None,
+        **params
+    ):
+        super().__init__(
+            error_key=error_key,
+            status_code=401,
+            error_code=error_code,
+            **params
+        )
+
+
+class ForbiddenError(I18nException):
+    """Forbidden error (403)."""
+
+    def __init__(
+        self,
+        error_key: str = "errors.auth.forbidden",
+        error_code: Optional[str] = None,
+        **params
+    ):
+        super().__init__(
+            error_key=error_key,
+            status_code=403,
+            error_code=error_code,
+            **params
+        )
+
+
+class NotFoundError(I18nException):
+    """Not found error (404)."""
+
+    def __init__(
+        self,
+        error_key: str = "errors.common.not_found",
+        error_code: Optional[str] = None,
+        **params
+    ):
+        super().__init__(
+            error_key=error_key,
+            status_code=404,
+            error_code=error_code,
+            **params
+        )
+
+
+class ConflictError(I18nException):
+    """Conflict error (409)."""
+
+    def __init__(
+        self,
+        error_key: str = "errors.common.conflict",
+        error_code: Optional[str] = None,
+        **params
+    ):
+        super().__init__(
+            error_key=error_key,
+            status_code=409,
+            error_code=error_code,
+            **params
+        )
+
+
+class ValidationError(I18nException):
+    """Validation error (422)."""
+
+    def __init__(
+        self,
+        error_key: str = "errors.common.validation_failed",
+        error_code: Optional[str] = None,
+        **params
+    ):
+        super().__init__(
+            error_key=error_key,
+            status_code=422,
+            error_code=error_code,
+            **params
+        )
+
+
+class InternalServerError(I18nException):
+    """Internal server error (500)."""
+
+    def __init__(
+        self,
+        error_key: str = "errors.common.internal_error",
+        error_code: Optional[str] = None,
+        **params
+    ):
+        super().__init__(
+            error_key=error_key,
+            status_code=500,
+            error_code=error_code,
+            **params
+        )
+
+
+class ServiceUnavailableError(I18nException):
+    """Service unavailable error (503)."""
+
+    def __init__(
+        self,
+        error_key: str = "errors.common.service_unavailable",
+        error_code: Optional[str] = None,
+        **params
+    ):
+        super().__init__(
+            error_key=error_key,
+            status_code=503,
+            error_code=error_code,
+            **params
+        )
+
+
+# Domain-specific exception classes
+
+class WorkspaceNotFoundError(NotFoundError):
+    """Workspace not found error."""
+
+    def __init__(self, workspace_id: Optional[str] = None, **params):
+        if workspace_id:
+            params["workspace_id"] = workspace_id
+        super().__init__(
+            error_key="errors.workspace.not_found",
+            error_code="WORKSPACE_NOT_FOUND",
+            **params
+        )
+
+
+class WorkspacePermissionDeniedError(ForbiddenError):
+    """Workspace permission denied error."""
+
+    def __init__(self, workspace_id: Optional[str] = None, **params):
+        if workspace_id:
+            params["workspace_id"] = workspace_id
+        super().__init__(
+            error_key="errors.workspace.permission_denied",
+            error_code="WORKSPACE_PERMISSION_DENIED",
+            **params
+        )
+
+
+class UserNotFoundError(NotFoundError):
+    """User not found error."""
+
+    def __init__(self, user_id: Optional[str] = None, **params):
+        if user_id:
+            params["user_id"] = user_id
+        super().__init__(
+            error_key="errors.user.not_found",
+            error_code="USER_NOT_FOUND",
+            **params
+        )
+
+
+class UserAlreadyExistsError(ConflictError):
+    """User already exists error."""
+
+    def __init__(self, identifier: Optional[str] = None, **params):
+        if identifier:
+            params["identifier"] = identifier
+        super().__init__(
+            error_key="errors.user.already_exists",
+            error_code="USER_ALREADY_EXISTS",
+            **params
+        )
+
+
+class TenantNotFoundError(NotFoundError):
+    """Tenant not found error."""
+
+    def __init__(self, tenant_id: Optional[str] = None, **params):
+        if tenant_id:
+            params["tenant_id"] = tenant_id
+        super().__init__(
+            error_key="errors.tenant.not_found",
+            error_code="TENANT_NOT_FOUND",
+            **params
+        )
+
+
+class TenantSuspendedError(ForbiddenError):
+    """Tenant suspended error."""
+
+    def __init__(self, tenant_id: Optional[str] = None, **params):
+        if tenant_id:
+            params["tenant_id"] = tenant_id
+        super().__init__(
+            error_key="errors.tenant.suspended",
+            error_code="TENANT_SUSPENDED",
+            **params
+        )
+
+
+class InvalidCredentialsError(UnauthorizedError):
+    """Invalid credentials error."""
+
+    def __init__(self, **params):
+        super().__init__(
+            error_key="errors.auth.invalid_credentials",
+            error_code="INVALID_CREDENTIALS",
+            **params
+        )
+
+
+class TokenExpiredError(UnauthorizedError):
+    """Token expired error."""
+
+    def __init__(self, **params):
+        super().__init__(
+            error_key="errors.auth.token_expired",
+            error_code="TOKEN_EXPIRED",
+            **params
+        )
+
+
+class TokenInvalidError(UnauthorizedError):
+    """Token invalid error."""
+
+    def __init__(self, **params):
+        super().__init__(
+            error_key="errors.auth.token_invalid",
+            error_code="TOKEN_INVALID",
+            **params
+        )
+
+
+class FileNotFoundError(NotFoundError):
+    """File not found error."""
+
+    def __init__(self, file_id: Optional[str] = None, **params):
+        if file_id:
+            params["file_id"] = file_id
+        super().__init__(
+            error_key="errors.file.not_found",
+            error_code="FILE_NOT_FOUND",
+            **params
+        )
+
+
+class FileTooLargeError(BadRequestError):
+    """File too large error."""
+
+    def __init__(self, max_size: Optional[str] = None, **params):
+        if max_size:
+            params["max_size"] = max_size
+        super().__init__(
+            error_key="errors.file.too_large",
+            error_code="FILE_TOO_LARGE",
+            **params
+        )
+
+
+class InvalidFileTypeError(BadRequestError):
+    """Invalid file type error."""
+
+    def __init__(self, file_type: Optional[str] = None, **params):
+        if file_type:
+            params["file_type"] = file_type
+        super().__init__(
+            error_key="errors.file.invalid_type",
+            error_code="INVALID_FILE_TYPE",
+            **params
+        )
+
+
+class RateLimitExceededError(I18nException):
+    """Rate limit exceeded error (429)."""
+
+    def __init__(self, **params):
+        super().__init__(
+            error_key="errors.api.rate_limit_exceeded",
+            status_code=429,
+            error_code="RATE_LIMIT_EXCEEDED",
+            **params
+        )
+
+
+class QuotaExceededError(ForbiddenError):
+    """Quota exceeded error."""
+
+    def __init__(self, resource: Optional[str] = None, **params):
+        if resource:
+            params["resource"] = resource
+        super().__init__(
+            error_key="errors.api.quota_exceeded",
+            error_code="QUOTA_EXCEEDED",
+            **params
+        )

api/app/i18n/loader.py

@@ -0,0 +1,199 @@
+"""
+Translation file loader for i18n system.
+
+This module handles loading translation files from multiple directories
+(community edition + enterprise edition) and provides hot reload support.
+"""
+
+import json
+import logging
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+
+logger = logging.getLogger(__name__)
+
+
+class TranslationLoader:
+    """
+    Translation file loader that supports:
+    - Loading from multiple directories (community + enterprise)
+    - Hot reload of translation files
+    - Automatic locale detection
+    """
+
+    def __init__(self, locales_dirs: Optional[List[str]] = None):
+        """
+        Initialize the translation loader.
+
+        Args:
+            locales_dirs: List of directories containing translation files.
+                         If None, will auto-detect from settings.
+        """
+        if locales_dirs is None:
+            locales_dirs = self._detect_locales_dirs()
+
+        self.locales_dirs = [Path(d) for d in locales_dirs]
+        logger.info(f"TranslationLoader initialized with directories: {self.locales_dirs}")
+
+    def _detect_locales_dirs(self) -> List[str]:
+        """
+        Auto-detect translation directories from settings.
+
+        Returns:
+            List of translation directory paths
+        """
+        from app.core.config import settings
+
+        dirs = []
+
+        # 1. Core locales directory (community edition, required)
+        core_dir = Path(settings.I18N_CORE_LOCALES_DIR)
+        if core_dir.exists():
+            dirs.append(str(core_dir))
+            logger.debug(f"Found core locales directory: {core_dir}")
+        else:
+            logger.warning(f"Core locales directory not found: {core_dir}")
+
+        # 2. Premium locales directory (enterprise edition, optional)
+        if settings.I18N_PREMIUM_LOCALES_DIR:
+            premium_dir = Path(settings.I18N_PREMIUM_LOCALES_DIR)
+            if premium_dir.exists():
+                dirs.append(str(premium_dir))
+                logger.debug(f"Found premium locales directory: {premium_dir}")
+        else:
+            # Auto-detect premium directory
+            premium_dir = Path("premium/locales")
+            if premium_dir.exists():
+                dirs.append(str(premium_dir))
+                logger.debug(f"Auto-detected premium locales directory: {premium_dir}")
+
+        if not dirs:
+            logger.error("No translation directories found!")
+
+        return dirs
+
+    def get_available_locales(self) -> List[str]:
+        """
+        Get list of all available locales across all directories.
+
+        Returns:
+            List of locale codes (e.g., ['zh', 'en'])
+        """
+        locales = set()
+
+        for locales_dir in self.locales_dirs:
+            if not locales_dir.exists():
+                continue
+
+            for locale_dir in locales_dir.iterdir():
+                if locale_dir.is_dir() and not locale_dir.name.startswith('.'):
+                    locales.add(locale_dir.name)
+
+        return sorted(list(locales))
+
+    def load_locale(self, locale: str) -> Dict[str, Any]:
+        """
+        Load all translation files for a specific locale from all directories.
+
+        Translation files are merged with priority:
+        - Later directories override earlier directories
+        - Enterprise translations override community translations
+
+        Args:
+            locale: Locale code (e.g., 'zh', 'en')
+
+        Returns:
+            Dictionary of translations organized by namespace
+            Format: {namespace: {key: value, ...}, ...}
+        """
+        translations = {}
+
+        # Load from each directory in order (later directories override earlier)
+        for locales_dir in self.locales_dirs:
+            locale_dir = locales_dir / locale
+            if not locale_dir.exists():
+                logger.debug(f"Locale directory not found: {locale_dir}")
+                continue
+
+            # Load all JSON files in this locale directory
+            for json_file in locale_dir.glob("*.json"):
+                namespace = json_file.stem
+
+                try:
+                    with open(json_file, "r", encoding="utf-8") as f:
+                        new_translations = json.load(f)
+
+                    # Merge translations (deep merge)
+                    if namespace in translations:
+                        translations[namespace] = self._deep_merge(
+                            translations[namespace],
+                            new_translations
+                        )
+                        logger.debug(
+                            f"Merged translations: {locale}/{namespace} from {json_file}"
+                        )
+                    else:
+                        translations[namespace] = new_translations
+                        logger.debug(
+                            f"Loaded translations: {locale}/{namespace} from {json_file}"
+                        )
+
+                except json.JSONDecodeError as e:
+                    logger.error(
+                        f"Failed to parse JSON file {json_file}: {e}"
+                    )
+                except Exception as e:
+                    logger.error(
+                        f"Failed to load translation file {json_file}: {e}"
+                    )
+
+        if not translations:
+            logger.warning(f"No translations found for locale: {locale}")
+
+        return translations
+
+    def reload(self, locale: Optional[str] = None) -> Dict[str, Dict[str, Any]]:
+        """
+        Reload translation files.
+
+        Args:
+            locale: Specific locale to reload. If None, reloads all locales.
+
+        Returns:
+            Dictionary of reloaded translations
+            Format: {locale: {namespace: {key: value}}}
+        """
+        if locale:
+            logger.info(f"Reloading translations for locale: {locale}")
+            return {locale: self.load_locale(locale)}
+        else:
+            logger.info("Reloading all translations")
+            all_translations = {}
+            for loc in self.get_available_locales():
+                all_translations[loc] = self.load_locale(loc)
+            return all_translations
+
+    def _deep_merge(self, base: Dict, override: Dict) -> Dict:
+        """
+        Deep merge two dictionaries.
+
+        Args:
+            base: Base dictionary
+            override: Dictionary with values to override
+
+        Returns:
+            Merged dictionary
+        """
+        result = base.copy()
+
+        for key, value in override.items():
+            if (
+                key in result
+                and isinstance(result[key], dict)
+                and isinstance(value, dict)
+            ):
+                result[key] = self._deep_merge(result[key], value)
+            else:
+                result[key] = value
+
+        return result

api/app/i18n/logger.py

@@ -0,0 +1,382 @@
+"""
+Translation logging for i18n system.
+
+This module provides:
+- TranslationLogger for recording missing translations
+- Missing translation report generation
+- Integration with existing logging system
+- Structured logging for translation events
+"""
+
+import logging
+from typing import Dict, List, Optional, Set
+from datetime import datetime
+from collections import defaultdict
+from pathlib import Path
+import json
+
+from app.core.logging_config import get_logger
+
+logger = get_logger(__name__)
+
+
+class TranslationLogger:
+    """
+    Logger for translation events and missing translations.
+    
+    Features:
+    - Records missing translations with context
+    - Generates missing translation reports
+    - Integrates with existing logging system
+    - Provides structured logging for analysis
+    """
+    
+    def __init__(self, log_file: Optional[str] = None):
+        """
+        Initialize translation logger.
+        
+        Args:
+            log_file: Optional custom log file path for missing translations
+        """
+        self.log_file = log_file or "logs/i18n/missing_translations.log"
+        self._missing_translations: Dict[str, Set[str]] = defaultdict(set)
+        self._missing_with_context: List[Dict] = []
+        self._max_context_entries = 10000  # Keep last 10k entries
+        
+        # Ensure log directory exists
+        log_path = Path(self.log_file)
+        log_path.parent.mkdir(parents=True, exist_ok=True)
+        
+        # Create dedicated file handler for missing translations
+        self._file_handler = logging.FileHandler(
+            self.log_file,
+            encoding='utf-8'
+        )
+        self._file_handler.setLevel(logging.WARNING)
+        
+        # Create formatter
+        formatter = logging.Formatter(
+            fmt='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
+            datefmt='%Y-%m-%d %H:%M:%S'
+        )
+        self._file_handler.setFormatter(formatter)
+        
+        # Create dedicated logger for missing translations
+        self._logger = logging.getLogger("i18n.missing_translations")
+        self._logger.setLevel(logging.WARNING)
+        self._logger.addHandler(self._file_handler)
+        self._logger.propagate = False  # Don't propagate to root logger
+        
+        logger.info(f"TranslationLogger initialized with log file: {self.log_file}")
+    
+    def log_missing_translation(
+        self,
+        key: str,
+        locale: str,
+        context: Optional[Dict] = None
+    ):
+        """
+        Log a missing translation.
+        
+        Args:
+            key: Translation key that was not found
+            locale: Locale code
+            context: Optional context information (e.g., request path, user info)
+        """
+        # Add to missing set
+        self._missing_translations[locale].add(key)
+        
+        # Create context entry
+        entry = {
+            "timestamp": datetime.now().isoformat(),
+            "key": key,
+            "locale": locale,
+            "context": context or {}
+        }
+        
+        # Keep only recent entries to avoid memory bloat
+        if len(self._missing_with_context) >= self._max_context_entries:
+            self._missing_with_context.pop(0)
+        
+        self._missing_with_context.append(entry)
+        
+        # Log to file
+        context_str = f" (context: {context})" if context else ""
+        self._logger.warning(
+            f"Missing translation: key='{key}', locale='{locale}'{context_str}"
+        )
+    
+    def log_translation_error(
+        self,
+        error_type: str,
+        message: str,
+        key: Optional[str] = None,
+        locale: Optional[str] = None,
+        context: Optional[Dict] = None
+    ):
+        """
+        Log a translation error.
+        
+        Args:
+            error_type: Type of error (e.g., "format_error", "parameter_missing")
+            message: Error message
+            key: Translation key (optional)
+            locale: Locale code (optional)
+            context: Optional context information
+        """
+        error_data = {
+            "error_type": error_type,
+            "message": message,
+            "key": key,
+            "locale": locale,
+            "context": context or {},
+            "timestamp": datetime.now().isoformat()
+        }
+        
+        self._logger.error(
+            f"Translation error: {error_type} - {message} "
+            f"(key: {key}, locale: {locale})"
+        )
+    
+    def log_translation_success(
+        self,
+        key: str,
+        locale: str,
+        duration_ms: Optional[float] = None
+    ):
+        """
+        Log a successful translation (debug level).
+        
+        Args:
+            key: Translation key
+            locale: Locale code
+            duration_ms: Optional duration in milliseconds
+        """
+        duration_str = f" ({duration_ms:.3f}ms)" if duration_ms else ""
+        logger.debug(
+            f"Translation success: key='{key}', locale='{locale}'{duration_str}"
+        )
+    
+    def get_missing_translations(
+        self,
+        locale: Optional[str] = None
+    ) -> Dict[str, List[str]]:
+        """
+        Get missing translations.
+        
+        Args:
+            locale: Specific locale (optional, returns all if None)
+            
+        Returns:
+            Dictionary of missing translations by locale
+        """
+        if locale:
+            return {locale: sorted(list(self._missing_translations.get(locale, set())))}
+        
+        return {
+            loc: sorted(list(keys))
+            for loc, keys in self._missing_translations.items()
+        }
+    
+    def get_missing_with_context(
+        self,
+        locale: Optional[str] = None,
+        limit: Optional[int] = None
+    ) -> List[Dict]:
+        """
+        Get missing translations with context.
+        
+        Args:
+            locale: Filter by locale (optional)
+            limit: Maximum number of entries to return (optional)
+            
+        Returns:
+            List of missing translation entries with context
+        """
+        entries = self._missing_with_context
+        
+        # Filter by locale if specified
+        if locale:
+            entries = [e for e in entries if e["locale"] == locale]
+        
+        # Apply limit if specified
+        if limit:
+            entries = entries[-limit:]
+        
+        return entries
+    
+    def generate_report(
+        self,
+        locale: Optional[str] = None,
+        output_file: Optional[str] = None
+    ) -> Dict:
+        """
+        Generate a missing translation report.
+        
+        Args:
+            locale: Specific locale (optional, generates for all if None)
+            output_file: Optional file path to save report as JSON
+            
+        Returns:
+            Report dictionary
+        """
+        missing = self.get_missing_translations(locale)
+        
+        report = {
+            "generated_at": datetime.now().isoformat(),
+            "total_missing": sum(len(keys) for keys in missing.values()),
+            "missing_by_locale": {
+                loc: {
+                    "count": len(keys),
+                    "keys": keys
+                }
+                for loc, keys in missing.items()
+            },
+            "recent_context": self.get_missing_with_context(locale, limit=100)
+        }
+        
+        # Save to file if specified
+        if output_file:
+            output_path = Path(output_file)
+            output_path.parent.mkdir(parents=True, exist_ok=True)
+            
+            with open(output_path, 'w', encoding='utf-8') as f:
+                json.dump(report, f, indent=2, ensure_ascii=False)
+            
+            logger.info(f"Missing translation report saved to: {output_file}")
+        
+        return report
+    
+    def get_statistics(self) -> Dict:
+        """
+        Get statistics about missing translations.
+        
+        Returns:
+            Dictionary with statistics
+        """
+        total_missing = sum(len(keys) for keys in self._missing_translations.values())
+        
+        # Count by namespace
+        namespace_counts = defaultdict(int)
+        for locale, keys in self._missing_translations.items():
+            for key in keys:
+                namespace = key.split('.')[0] if '.' in key else 'unknown'
+                namespace_counts[namespace] += 1
+        
+        return {
+            "total_missing": total_missing,
+            "locales_affected": len(self._missing_translations),
+            "missing_by_locale": {
+                loc: len(keys)
+                for loc, keys in self._missing_translations.items()
+            },
+            "missing_by_namespace": dict(namespace_counts),
+            "total_context_entries": len(self._missing_with_context)
+        }
+    
+    def clear(self, locale: Optional[str] = None):
+        """
+        Clear missing translation records.
+        
+        Args:
+            locale: Specific locale to clear (optional, clears all if None)
+        """
+        if locale:
+            self._missing_translations.pop(locale, None)
+            self._missing_with_context = [
+                e for e in self._missing_with_context
+                if e["locale"] != locale
+            ]
+            logger.info(f"Cleared missing translations for locale: {locale}")
+        else:
+            self._missing_translations.clear()
+            self._missing_with_context.clear()
+            logger.info("Cleared all missing translations")
+    
+    def export_to_json(self, output_file: str):
+        """
+        Export all missing translations to JSON file.
+        
+        Args:
+            output_file: Output file path
+        """
+        data = {
+            "exported_at": datetime.now().isoformat(),
+            "missing_translations": self.get_missing_translations(),
+            "statistics": self.get_statistics(),
+            "recent_context": self.get_missing_with_context(limit=1000)
+        }
+        
+        output_path = Path(output_file)
+        output_path.parent.mkdir(parents=True, exist_ok=True)
+        
+        with open(output_path, 'w', encoding='utf-8') as f:
+            json.dump(data, f, indent=2, ensure_ascii=False)
+        
+        logger.info(f"Missing translations exported to: {output_file}")
+    
+    def __del__(self):
+        """Cleanup file handler on deletion."""
+        try:
+            if hasattr(self, '_file_handler'):
+                self._file_handler.close()
+                self._logger.removeHandler(self._file_handler)
+        except Exception:
+            pass
+
+
+# Global translation logger instance
+_translation_logger: Optional[TranslationLogger] = None
+
+
+def get_translation_logger() -> TranslationLogger:
+    """
+    Get the global translation logger instance.
+    
+    Returns:
+        TranslationLogger singleton
+    """
+    global _translation_logger
+    if _translation_logger is None:
+        _translation_logger = TranslationLogger()
+    return _translation_logger
+
+
+def log_missing_translation(
+    key: str,
+    locale: str,
+    context: Optional[Dict] = None
+):
+    """
+    Log a missing translation (convenience function).
+    
+    Args:
+        key: Translation key
+        locale: Locale code
+        context: Optional context information
+    """
+    translation_logger = get_translation_logger()
+    translation_logger.log_missing_translation(key, locale, context)
+
+
+def log_translation_error(
+    error_type: str,
+    message: str,
+    key: Optional[str] = None,
+    locale: Optional[str] = None,
+    context: Optional[Dict] = None
+):
+    """
+    Log a translation error (convenience function).
+    
+    Args:
+        error_type: Type of error
+        message: Error message
+        key: Translation key (optional)
+        locale: Locale code (optional)
+        context: Optional context information
+    """
+    translation_logger = get_translation_logger()
+    translation_logger.log_translation_error(
+        error_type, message, key, locale, context
+    )

api/app/i18n/metrics.py

@@ -0,0 +1,337 @@
+"""
+Performance monitoring and metrics for i18n system.
+
+This module provides:
+- Translation request counters
+- Translation timing metrics
+- Missing translation tracking
+- Performance monitoring decorators
+- Prometheus-compatible metrics
+"""
+
+import logging
+import time
+from functools import wraps
+from typing import Any, Callable, Dict, Optional
+from collections import defaultdict
+from datetime import datetime
+
+logger = logging.getLogger(__name__)
+
+
+class TranslationMetrics:
+    """
+    Metrics collector for translation operations.
+    
+    Tracks:
+    - Translation request counts
+    - Translation timing (latency)
+    - Missing translations
+    - Cache performance
+    - Locale usage
+    """
+    
+    def __init__(self):
+        """Initialize metrics collector."""
+        # Request counters by locale
+        self._request_counts: Dict[str, int] = defaultdict(int)
+        
+        # Missing translation tracker
+        self._missing_translations: Dict[str, set] = defaultdict(set)
+        
+        # Timing metrics (in milliseconds)
+        self._timing_data: list = []
+        self._max_timing_samples = 10000  # Keep last 10k samples
+        
+        # Locale usage
+        self._locale_usage: Dict[str, int] = defaultdict(int)
+        
+        # Namespace usage
+        self._namespace_usage: Dict[str, int] = defaultdict(int)
+        
+        # Error counts
+        self._error_counts: Dict[str, int] = defaultdict(int)
+        
+        # Start time
+        self._start_time = datetime.now()
+        
+        logger.info("TranslationMetrics initialized")
+    
+    def record_request(self, locale: str, namespace: str = None):
+        """
+        Record a translation request.
+        
+        Args:
+            locale: Locale code
+            namespace: Translation namespace (optional)
+        """
+        self._request_counts[locale] += 1
+        self._locale_usage[locale] += 1
+        
+        if namespace:
+            self._namespace_usage[namespace] += 1
+    
+    def record_missing(self, key: str, locale: str):
+        """
+        Record a missing translation.
+        
+        Args:
+            key: Translation key
+            locale: Locale code
+        """
+        self._missing_translations[locale].add(key)
+        logger.debug(f"Missing translation recorded: {key} (locale: {locale})")
+    
+    def record_timing(self, duration_ms: float, locale: str, operation: str = "translate"):
+        """
+        Record translation operation timing.
+        
+        Args:
+            duration_ms: Duration in milliseconds
+            locale: Locale code
+            operation: Operation type
+        """
+        # Keep only recent samples to avoid memory bloat
+        if len(self._timing_data) >= self._max_timing_samples:
+            self._timing_data.pop(0)
+        
+        self._timing_data.append({
+            "duration_ms": duration_ms,
+            "locale": locale,
+            "operation": operation,
+            "timestamp": time.time()
+        })
+    
+    def record_error(self, error_type: str):
+        """
+        Record an error.
+        
+        Args:
+            error_type: Type of error
+        """
+        self._error_counts[error_type] += 1
+    
+    def get_summary(self) -> Dict[str, Any]:
+        """
+        Get metrics summary.
+        
+        Returns:
+            Dictionary with metrics summary
+        """
+        total_requests = sum(self._request_counts.values())
+        total_missing = sum(len(keys) for keys in self._missing_translations.values())
+        
+        # Calculate timing statistics
+        timing_stats = self._calculate_timing_stats()
+        
+        # Calculate uptime
+        uptime_seconds = (datetime.now() - self._start_time).total_seconds()
+        
+        return {
+            "uptime_seconds": round(uptime_seconds, 2),
+            "total_requests": total_requests,
+            "requests_per_locale": dict(self._request_counts),
+            "total_missing_translations": total_missing,
+            "missing_by_locale": {
+                locale: len(keys)
+                for locale, keys in self._missing_translations.items()
+            },
+            "timing": timing_stats,
+            "locale_usage": dict(self._locale_usage),
+            "namespace_usage": dict(self._namespace_usage),
+            "error_counts": dict(self._error_counts)
+        }
+    
+    def _calculate_timing_stats(self) -> Dict[str, Any]:
+        """
+        Calculate timing statistics.
+        
+        Returns:
+            Dictionary with timing statistics
+        """
+        if not self._timing_data:
+            return {
+                "count": 0,
+                "avg_ms": 0,
+                "min_ms": 0,
+                "max_ms": 0,
+                "p50_ms": 0,
+                "p95_ms": 0,
+                "p99_ms": 0
+            }
+        
+        durations = [d["duration_ms"] for d in self._timing_data]
+        durations.sort()
+        
+        count = len(durations)
+        avg = sum(durations) / count
+        
+        # Calculate percentiles
+        p50_idx = int(count * 0.50)
+        p95_idx = int(count * 0.95)
+        p99_idx = int(count * 0.99)
+        
+        return {
+            "count": count,
+            "avg_ms": round(avg, 3),
+            "min_ms": round(durations[0], 3),
+            "max_ms": round(durations[-1], 3),
+            "p50_ms": round(durations[p50_idx], 3),
+            "p95_ms": round(durations[p95_idx], 3),
+            "p99_ms": round(durations[p99_idx], 3)
+        }
+    
+    def get_missing_translations(self, locale: Optional[str] = None) -> Dict[str, list]:
+        """
+        Get missing translations.
+        
+        Args:
+            locale: Specific locale (optional, returns all if None)
+            
+        Returns:
+            Dictionary of missing translations by locale
+        """
+        if locale:
+            return {locale: list(self._missing_translations.get(locale, set()))}
+        
+        return {
+            locale: list(keys)
+            for locale, keys in self._missing_translations.items()
+        }
+    
+    def reset(self):
+        """Reset all metrics."""
+        self._request_counts.clear()
+        self._missing_translations.clear()
+        self._timing_data.clear()
+        self._locale_usage.clear()
+        self._namespace_usage.clear()
+        self._error_counts.clear()
+        self._start_time = datetime.now()
+        logger.info("Metrics reset")
+    
+    def export_prometheus(self) -> str:
+        """
+        Export metrics in Prometheus format.
+        
+        Returns:
+            Prometheus-formatted metrics string
+        """
+        lines = []
+        
+        # Translation requests counter
+        lines.append("# HELP i18n_translation_requests_total Total number of translation requests")
+        lines.append("# TYPE i18n_translation_requests_total counter")
+        for locale, count in self._request_counts.items():
+            lines.append(f'i18n_translation_requests_total{{locale="{locale}"}} {count}')
+        
+        # Missing translations counter
+        lines.append("# HELP i18n_missing_translations_total Total number of missing translations")
+        lines.append("# TYPE i18n_missing_translations_total counter")
+        for locale, keys in self._missing_translations.items():
+            lines.append(f'i18n_missing_translations_total{{locale="{locale}"}} {len(keys)}')
+        
+        # Timing metrics
+        timing_stats = self._calculate_timing_stats()
+        lines.append("# HELP i18n_translation_duration_ms Translation operation duration in milliseconds")
+        lines.append("# TYPE i18n_translation_duration_ms summary")
+        lines.append(f'i18n_translation_duration_ms{{quantile="0.5"}} {timing_stats["p50_ms"]}')
+        lines.append(f'i18n_translation_duration_ms{{quantile="0.95"}} {timing_stats["p95_ms"]}')
+        lines.append(f'i18n_translation_duration_ms{{quantile="0.99"}} {timing_stats["p99_ms"]}')
+        lines.append(f'i18n_translation_duration_ms_sum {sum(d["duration_ms"] for d in self._timing_data)}')
+        lines.append(f'i18n_translation_duration_ms_count {timing_stats["count"]}')
+        
+        # Error counter
+        lines.append("# HELP i18n_errors_total Total number of i18n errors")
+        lines.append("# TYPE i18n_errors_total counter")
+        for error_type, count in self._error_counts.items():
+            lines.append(f'i18n_errors_total{{type="{error_type}"}} {count}')
+        
+        return "\n".join(lines)
+
+
+# Global metrics instance
+_metrics: Optional[TranslationMetrics] = None
+
+
+def get_metrics() -> TranslationMetrics:
+    """
+    Get the global metrics instance.
+    
+    Returns:
+        TranslationMetrics singleton
+    """
+    global _metrics
+    if _metrics is None:
+        _metrics = TranslationMetrics()
+    return _metrics
+
+
+def monitor_performance(operation: str = "translate"):
+    """
+    Decorator to monitor translation operation performance.
+    
+    Args:
+        operation: Operation name for metrics
+        
+    Returns:
+        Decorated function
+        
+    Example:
+        @monitor_performance("translate")
+        def translate(key: str, locale: str) -> str:
+            ...
+    """
+    def decorator(func: Callable) -> Callable:
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            start_time = time.perf_counter()
+            
+            try:
+                result = func(*args, **kwargs)
+                
+                # Record timing
+                duration_ms = (time.perf_counter() - start_time) * 1000
+                
+                # Try to extract locale from args/kwargs
+                locale = kwargs.get("locale", "unknown")
+                if not locale and len(args) > 1:
+                    locale = args[1] if isinstance(args[1], str) else "unknown"
+                
+                metrics = get_metrics()
+                metrics.record_timing(duration_ms, locale, operation)
+                
+                return result
+            
+            except Exception as e:
+                # Record error
+                metrics = get_metrics()
+                metrics.record_error(type(e).__name__)
+                raise
+        
+        return wrapper
+    return decorator
+
+
+def track_missing_translation(key: str, locale: str):
+    """
+    Track a missing translation.
+    
+    Args:
+        key: Translation key
+        locale: Locale code
+    """
+    metrics = get_metrics()
+    metrics.record_missing(key, locale)
+
+
+def track_translation_request(locale: str, namespace: str = None):
+    """
+    Track a translation request.
+    
+    Args:
+        locale: Locale code
+        namespace: Translation namespace (optional)
+    """
+    metrics = get_metrics()
+    metrics.record_request(locale, namespace)

api/app/i18n/middleware.py

@@ -0,0 +1,202 @@
+"""
+Language detection middleware for i18n system.
+
+This middleware determines the language to use for each request based on:
+1. Query parameter (?lang=en)
+2. Accept-Language HTTP header
+3. User language preference (from database)
+4. Tenant default language
+5. System default language
+
+The detected language is injected into request.state.language and
+added to the response Content-Language header.
+"""
+
+import logging
+import re
+from typing import Optional
+
+from fastapi import Request
+from starlette.middleware.base import BaseHTTPMiddleware
+
+logger = logging.getLogger(__name__)
+
+
+class LanguageMiddleware(BaseHTTPMiddleware):
+    """
+    Language detection middleware.
+    
+    Determines the language for each request based on multiple sources
+    with a clear priority order, validates the language is supported,
+    and injects it into the request context.
+    """
+
+    async def dispatch(self, request: Request, call_next):
+        """
+        Process the request and determine the language.
+        
+        Args:
+            request: The incoming request
+            call_next: The next middleware/handler in the chain
+            
+        Returns:
+            Response with Content-Language header added
+        """
+        # Determine the language for this request
+        language = await self._determine_language(request)
+        
+        # Validate language is supported
+        from app.core.config import settings
+        if language not in settings.I18N_SUPPORTED_LANGUAGES:
+            logger.warning(
+                f"Unsupported language '{language}' requested, "
+                f"falling back to default: {settings.I18N_DEFAULT_LANGUAGE}"
+            )
+            language = settings.I18N_DEFAULT_LANGUAGE
+        
+        # Inject language into request state
+        request.state.language = language
+        
+        # Also set in context variable for exception handling
+        from app.i18n.exceptions import set_current_locale
+        set_current_locale(language)
+        
+        logger.debug(f"Request language set to: {language}")
+        
+        # Process the request
+        response = await call_next(request)
+        
+        # Add Content-Language header to response
+        response.headers["Content-Language"] = language
+        
+        return response
+
+    async def _determine_language(self, request: Request) -> str:
+        """
+        Determine the language to use based on priority order.
+        
+        Priority:
+        1. Query parameter (?lang=en)
+        2. Accept-Language HTTP header
+        3. User language preference (from database)
+        4. Tenant default language
+        5. System default language
+        
+        Args:
+            request: The incoming request
+            
+        Returns:
+            Language code (e.g., "zh", "en")
+        """
+        from app.core.config import settings
+        
+        # 1. Check query parameter (?lang=en)
+        if "lang" in request.query_params:
+            lang = request.query_params["lang"].strip().lower()
+            if lang:
+                logger.debug(f"Language from query parameter: {lang}")
+                return lang
+        
+        # 2. Check Accept-Language HTTP header
+        if "Accept-Language" in request.headers:
+            lang = self._parse_accept_language(
+                request.headers["Accept-Language"]
+            )
+            if lang:
+                logger.debug(f"Language from Accept-Language header: {lang}")
+                return lang
+        
+        # 3. Check user language preference (requires authentication)
+        # Note: This assumes user is already loaded into request.state by auth middleware
+        if hasattr(request.state, "user") and request.state.user:
+            user = request.state.user
+            if hasattr(user, "preferred_language") and user.preferred_language:
+                logger.debug(
+                    f"Language from user preference: {user.preferred_language}"
+                )
+                return user.preferred_language
+        
+        # 4. Check tenant default language
+        # Note: This assumes tenant is already loaded into request.state
+        if hasattr(request.state, "tenant") and request.state.tenant:
+            tenant = request.state.tenant
+            if hasattr(tenant, "default_language") and tenant.default_language:
+                logger.debug(
+                    f"Language from tenant default: {tenant.default_language}"
+                )
+                return tenant.default_language
+        
+        # 5. Fall back to system default language
+        logger.debug(
+            f"Using system default language: {settings.I18N_DEFAULT_LANGUAGE}"
+        )
+        return settings.I18N_DEFAULT_LANGUAGE
+
+    def _parse_accept_language(self, header: str) -> Optional[str]:
+        """
+        Parse the Accept-Language HTTP header.
+        
+        The Accept-Language header format:
+        Accept-Language: zh-CN,zh;q=0.9,en;q=0.8,en-US;q=0.7
+        
+        This method:
+        1. Parses all language codes and their quality values
+        2. Extracts the base language code (zh-CN -> zh)
+        3. Sorts by quality value (higher first)
+        4. Returns the first supported language
+        
+        Args:
+            header: Accept-Language header value
+            
+        Returns:
+            Language code if found and supported, None otherwise
+            
+        Examples:
+            _parse_accept_language("zh-CN,zh;q=0.9,en;q=0.8")
+            # => "zh" (if zh is supported)
+            
+            _parse_accept_language("en-US,en;q=0.9")
+            # => "en" (if en is supported)
+        """
+        from app.core.config import settings
+        
+        if not header:
+            return None
+        
+        # Parse language preferences with quality values
+        languages = []
+        
+        for item in header.split(","):
+            item = item.strip()
+            if not item:
+                continue
+            
+            # Split language code and quality value
+            parts = item.split(";")
+            lang_code = parts[0].strip()
+            
+            # Extract base language code (zh-CN -> zh, en-US -> en)
+            base_lang = lang_code.split("-")[0].lower()
+            
+            # Extract quality value (default: 1.0)
+            quality = 1.0
+            if len(parts) > 1:
+                # Look for q=0.9 pattern
+                q_match = re.search(r"q=([\d.]+)", parts[1])
+                if q_match:
+                    try:
+                        quality = float(q_match.group(1))
+                    except ValueError:
+                        quality = 1.0
+            
+            languages.append((base_lang, quality))
+        
+        # Sort by quality value (descending)
+        languages.sort(key=lambda x: x[1], reverse=True)
+        
+        # Return the first supported language
+        for lang_code, _ in languages:
+            if lang_code in settings.I18N_SUPPORTED_LANGUAGES:
+                return lang_code
+        
+        return None

api/app/i18n/serializers.py

@@ -0,0 +1,219 @@
+"""
+国际化响应序列化器
+
+提供基础的 I18nResponseMixin 类，用于为 API 响应添加国际化字段。
+"""
+
+from typing import Any, Dict, List, Union
+from pydantic import BaseModel
+
+
+class I18nResponseMixin:
+    """国际化响应混入类
+    
+    为响应数据添加国际化字段，特别是为枚举值添加 _display 后缀的翻译字段。
+    
+    使用方法：
+        1. 继承此类
+        2. 实现 _get_enum_fields() 方法定义需要翻译的枚举字段
+        3. 调用 serialize_with_i18n() 方法序列化数据
+    
+    示例：
+        class WorkspaceSerializer(I18nResponseMixin):
+            def _get_enum_fields(self) -> Dict[str, str]:
+                return {
+                    "role": "workspace_role",
+                    "status": "workspace_status"
+                }
+            
+            def serialize(self, workspace: Workspace, locale: str = "zh") -> Dict:
+                data = {
+                    "id": str(workspace.id),
+                    "name": workspace.name,
+                    "role": workspace.role,
+                    "status": workspace.status
+                }
+                return self.serialize_with_i18n(data, locale)
+    """
+    
+    def serialize_with_i18n(
+        self, 
+        data: Any, 
+        locale: str = "zh"
+    ) -> Union[Dict, List[Dict], Any]:
+        """序列化数据并添加国际化字段
+        
+        Args:
+            data: 要序列化的数据（字典、列表或 Pydantic 模型）
+            locale: 语言代码
+            
+        Returns:
+            序列化后的数据，包含国际化字段
+        """
+        # 如果是 Pydantic 模型，转换为字典
+        if isinstance(data, BaseModel):
+            data = data.model_dump()
+        
+        # 处理不同类型的数据
+        if isinstance(data, dict):
+            return self._serialize_dict(data, locale)
+        elif isinstance(data, list):
+            return [self._serialize_dict(item, locale) if isinstance(item, dict) else item for item in data]
+        else:
+            return data
+    
+    def _serialize_dict(self, data: Dict, locale: str) -> Dict:
+        """序列化字典并添加 _display 字段
+        
+        Args:
+            data: 字典数据
+            locale: 语言代码
+            
+        Returns:
+            添加了 _display 字段的字典
+        """
+        from app.i18n.service import translation_service
+        
+        result = data.copy()
+        
+        # 获取需要翻译的枚举字段
+        enum_fields = self._get_enum_fields()
+        
+        # 为每个枚举字段添加 _display 字段
+        for field, enum_type in enum_fields.items():
+            if field in result and result[field] is not None:
+                value = result[field]
+                # 翻译枚举值
+                display_value = translation_service.translate_enum(
+                    enum_type=enum_type,
+                    value=str(value),
+                    locale=locale
+                )
+                # 添加 _display 字段
+                result[f"{field}_display"] = display_value
+        
+        return result
+    
+    def _get_enum_fields(self) -> Dict[str, str]:
+        """获取需要翻译的枚举字段
+        
+        子类必须实现此方法，返回字段名到枚举类型的映射。
+        
+        Returns:
+            字段名到枚举类型的映射
+            例如: {"role": "workspace_role", "status": "workspace_status"}
+        """
+        return {}
+
+
+class WorkspaceSerializer(I18nResponseMixin):
+    """工作空间序列化器
+    
+    为工作空间响应添加国际化字段。
+    """
+    
+    def _get_enum_fields(self) -> Dict[str, str]:
+        """定义工作空间的枚举字段"""
+        return {
+            "role": "workspace_role",
+            "status": "workspace_status"
+        }
+    
+    def serialize(self, workspace_data: Union[Dict, BaseModel], locale: str = "zh") -> Dict:
+        """序列化工作空间数据
+        
+        Args:
+            workspace_data: 工作空间数据（字典或 Pydantic 模型）
+            locale: 语言代码
+            
+        Returns:
+            序列化后的工作空间数据，包含国际化字段
+        """
+        return self.serialize_with_i18n(workspace_data, locale)
+    
+    def serialize_list(self, workspaces: List[Union[Dict, BaseModel]], locale: str = "zh") -> List[Dict]:
+        """序列化工作空间列表
+        
+        Args:
+            workspaces: 工作空间列表
+            locale: 语言代码
+            
+        Returns:
+            序列化后的工作空间列表
+        """
+        return [self.serialize(ws, locale) for ws in workspaces]
+
+
+class WorkspaceMemberSerializer(I18nResponseMixin):
+    """工作空间成员序列化器
+    
+    为工作空间成员响应添加国际化字段。
+    """
+    
+    def _get_enum_fields(self) -> Dict[str, str]:
+        """定义工作空间成员的枚举字段"""
+        return {
+            "role": "workspace_role"
+        }
+    
+    def serialize(self, member_data: Union[Dict, BaseModel], locale: str = "zh") -> Dict:
+        """序列化工作空间成员数据
+        
+        Args:
+            member_data: 成员数据（字典或 Pydantic 模型）
+            locale: 语言代码
+            
+        Returns:
+            序列化后的成员数据，包含国际化字段
+        """
+        return self.serialize_with_i18n(member_data, locale)
+    
+    def serialize_list(self, members: List[Union[Dict, BaseModel]], locale: str = "zh") -> List[Dict]:
+        """序列化工作空间成员列表
+        
+        Args:
+            members: 成员列表
+            locale: 语言代码
+            
+        Returns:
+            序列化后的成员列表
+        """
+        return [self.serialize(member, locale) for member in members]
+
+
+class WorkspaceInviteSerializer(I18nResponseMixin):
+    """工作空间邀请序列化器
+    
+    为工作空间邀请响应添加国际化字段。
+    """
+    
+    def _get_enum_fields(self) -> Dict[str, str]:
+        """定义工作空间邀请的枚举字段"""
+        return {
+            "status": "invite_status",
+            "role": "workspace_role"
+        }
+    
+    def serialize(self, invite_data: Union[Dict, BaseModel], locale: str = "zh") -> Dict:
+        """序列化工作空间邀请数据
+        
+        Args:
+            invite_data: 邀请数据（字典或 Pydantic 模型）
+            locale: 语言代码
+            
+        Returns:
+            序列化后的邀请数据，包含国际化字段
+        """
+        return self.serialize_with_i18n(invite_data, locale)
+    
+    def serialize_list(self, invites: List[Union[Dict, BaseModel]], locale: str = "zh") -> List[Dict]:
+        """序列化工作空间邀请列表
+        
+        Args:
+            invites: 邀请列表
+            locale: 语言代码
+            
+        Returns:
+            序列化后的邀请列表
+        """
+        return [self.serialize(invite, locale) for invite in invites]

api/app/i18n/service.py

@@ -0,0 +1,370 @@
+"""
+Translation service for i18n system.
+
+This module provides the core translation functionality including:
+- Translation lookup with fallback mechanism
+- Parameterized message support
+- Enum value translation
+- Memory caching for performance
+- Performance monitoring and metrics
+"""
+
+import logging
+from functools import lru_cache
+from typing import Any, Dict, Optional
+
+from app.i18n.loader import TranslationLoader
+from app.i18n.cache import TranslationCache
+from app.i18n.metrics import get_metrics, monitor_performance, track_missing_translation, track_translation_request
+from app.i18n.logger import get_translation_logger
+
+logger = logging.getLogger(__name__)
+
+
+class TranslationService:
+    """
+    Translation service that provides:
+    - Fast translation lookup with memory cache
+    - Parameterized message support ({param} syntax)
+    - Fallback mechanism (current locale → default locale → key)
+    - Enum value translation
+    - Deep merge of multi-directory translations
+    """
+
+    def __init__(self, locales_dirs: Optional[list] = None):
+        """
+        Initialize the translation service.
+
+        Args:
+            locales_dirs: List of directories containing translation files.
+                         If None, will auto-detect from settings.
+        """
+        from app.core.config import settings
+
+        self.loader = TranslationLoader(locales_dirs)
+        self.default_locale = settings.I18N_DEFAULT_LANGUAGE
+        self.fallback_locale = settings.I18N_FALLBACK_LANGUAGE
+        self.log_missing = settings.I18N_LOG_MISSING_TRANSLATIONS
+        self.enable_cache = settings.I18N_ENABLE_TRANSLATION_CACHE
+
+        # Initialize advanced cache with LRU
+        lru_cache_size = getattr(settings, 'I18N_LRU_CACHE_SIZE', 1000)
+        self.cache = TranslationCache(
+            max_lru_size=lru_cache_size,
+            enable_lazy_load=False  # Load all at startup for now
+        )
+
+        # Load all translations into cache
+        self._load_all_locales()
+
+        # Initialize metrics
+        self.metrics = get_metrics()
+        
+        # Initialize translation logger
+        self.translation_logger = get_translation_logger()
+
+        logger.info(
+            f"TranslationService initialized with default locale: {self.default_locale}, "
+            f"LRU cache size: {lru_cache_size}"
+        )
+
+    def _load_all_locales(self):
+        """Load all available locales into memory cache."""
+        available_locales = self.loader.get_available_locales()
+        logger.info(f"Loading translations for locales: {available_locales}")
+
+        for locale in available_locales:
+            locale_data = self.loader.load_locale(locale)
+            self.cache.set_locale_data(locale, locale_data)
+
+        logger.info(f"Loaded {len(available_locales)} locales into cache")
+
+    @monitor_performance("translate")
+    def translate(
+        self,
+        key: str,
+        locale: Optional[str] = None,
+        **params
+    ) -> str:
+        """
+        Translate a key to the target locale.
+
+        Supports:
+        - Dot-separated keys (e.g., "common.success.created")
+        - Parameterized messages (e.g., "Hello {name}")
+        - Fallback mechanism
+
+        Args:
+            key: Translation key (format: "namespace.key.subkey")
+            locale: Target locale (defaults to default locale)
+            **params: Parameters for parameterized messages
+
+        Returns:
+            Translated string, or the key itself if translation not found
+
+        Examples:
+            translate("common.success.created", "zh")
+            # => "创建成功"
+
+            translate("common.validation.required", "zh", field="名称")
+            # => "名称不能为空"
+        """
+        if locale is None:
+            locale = self.default_locale
+
+        # Parse key (namespace.key.subkey)
+        parts = key.split(".", 1)
+        if len(parts) < 2:
+            if self.log_missing:
+                logger.warning(f"Invalid translation key format: {key}")
+            return key
+
+        namespace = parts[0]
+        key_path = parts[1].split(".")
+
+        # Track request
+        track_translation_request(locale, namespace)
+
+        # Get translation from cache
+        translation = self.cache.get_translation(locale, namespace, key_path)
+
+        # Fallback to default locale if not found
+        if translation is None and locale != self.fallback_locale:
+            translation = self.cache.get_translation(
+                self.fallback_locale, namespace, key_path
+            )
+
+        # If still not found, return the key itself
+        if translation is None:
+            if self.log_missing:
+                logger.warning(
+                    f"Missing translation: {key} (locale: {locale})"
+                )
+                track_missing_translation(key, locale)
+                
+                # Log to translation logger with context
+                self.translation_logger.log_missing_translation(
+                    key=key,
+                    locale=locale,
+                    context={"namespace": namespace}
+                )
+            return key
+
+        # Apply parameters if provided
+        if params:
+            try:
+                translation = translation.format(**params)
+            except KeyError as e:
+                error_msg = f"Missing parameter in translation '{key}': {e}"
+                logger.error(error_msg)
+                self.translation_logger.log_translation_error(
+                    error_type="parameter_missing",
+                    message=error_msg,
+                    key=key,
+                    locale=locale,
+                    context={"params": list(params.keys())}
+                )
+            except Exception as e:
+                error_msg = f"Error formatting translation '{key}': {e}"
+                logger.error(error_msg)
+                self.translation_logger.log_translation_error(
+                    error_type="format_error",
+                    message=error_msg,
+                    key=key,
+                    locale=locale
+                )
+
+        return translation
+
+    def _get_translation(
+        self,
+        locale: str,
+        namespace: str,
+        key_path: list
+    ) -> Optional[str]:
+        """
+        Get translation from cache (deprecated, use cache.get_translation).
+
+        Args:
+            locale: Locale code
+            namespace: Translation namespace
+            key_path: List of nested keys
+
+        Returns:
+            Translation string or None if not found
+        """
+        return self.cache.get_translation(locale, namespace, key_path)
+
+    @monitor_performance("translate_enum")
+    def translate_enum(
+        self,
+        enum_type: str,
+        value: str,
+        locale: Optional[str] = None
+    ) -> str:
+        """
+        Translate an enum value.
+
+        Args:
+            enum_type: Enum type name (e.g., "workspace_role")
+            value: Enum value (e.g., "manager")
+            locale: Target locale
+
+        Returns:
+            Translated enum display name
+
+        Examples:
+            translate_enum("workspace_role", "manager", "zh")
+            # => "管理员"
+
+            translate_enum("invite_status", "pending", "en")
+            # => "Pending"
+        """
+        key = f"enums.{enum_type}.{value}"
+        return self.translate(key, locale)
+
+    def has_translation(self, key: str, locale: str) -> bool:
+        """
+        Check if a translation exists for the given key and locale.
+
+        Args:
+            key: Translation key
+            locale: Locale code
+
+        Returns:
+            True if translation exists, False otherwise
+        """
+        parts = key.split(".", 1)
+        if len(parts) < 2:
+            return False
+
+        namespace = parts[0]
+        key_path = parts[1].split(".")
+
+        translation = self.cache.get_translation(locale, namespace, key_path)
+        return translation is not None
+
+    def reload(self, locale: Optional[str] = None):
+        """
+        Reload translation files.
+
+        Args:
+            locale: Specific locale to reload. If None, reloads all locales.
+        """
+        logger.info(f"Reloading translations for locale: {locale or 'all'}")
+
+        if locale:
+            locale_data = self.loader.load_locale(locale)
+            self.cache.set_locale_data(locale, locale_data)
+            # Clear LRU cache for this locale
+            self.cache.clear_locale(locale)
+        else:
+            self._load_all_locales()
+            # Clear all LRU cache
+            self.cache.clear_lru()
+
+        logger.info("Translation reload completed")
+
+    def get_available_locales(self) -> list:
+        """
+        Get list of all available locales.
+
+        Returns:
+            List of locale codes
+        """
+        return self.cache.get_loaded_locales()
+    
+    def get_cache_stats(self) -> Dict[str, Any]:
+        """
+        Get cache statistics.
+        
+        Returns:
+            Dictionary with cache statistics
+        """
+        return self.cache.get_stats()
+    
+    def get_metrics_summary(self) -> Dict[str, Any]:
+        """
+        Get metrics summary.
+        
+        Returns:
+            Dictionary with metrics summary
+        """
+        return self.metrics.get_summary()
+    
+    def get_memory_usage(self) -> Dict[str, Any]:
+        """
+        Get memory usage information.
+        
+        Returns:
+            Dictionary with memory usage information
+        """
+        return self.cache.get_memory_usage()
+
+    def get_loaded_dirs(self) -> list:
+        """
+        Get list of loaded translation directories.
+
+        Returns:
+            List of directory paths
+        """
+        return self.loader.locales_dirs
+
+
+# Global singleton instance
+_translation_service: Optional[TranslationService] = None
+
+
+def get_translation_service() -> TranslationService:
+    """
+    Get the global translation service instance.
+
+    Returns:
+        TranslationService singleton
+    """
+    global _translation_service
+    if _translation_service is None:
+        _translation_service = TranslationService()
+    return _translation_service
+
+
+# Convenience functions for easy access
+def t(key: str, locale: Optional[str] = None, **params) -> str:
+    """
+    Translate a key (convenience function).
+
+    Args:
+        key: Translation key
+        locale: Target locale (optional, uses default if not provided)
+        **params: Parameters for parameterized messages
+
+    Returns:
+        Translated string
+
+    Examples:
+        t("common.success.created")
+        t("common.validation.required", field="名称")
+        t("workspace.member_count", count=5)
+    """
+    service = get_translation_service()
+    return service.translate(key, locale, **params)
+
+
+def t_enum(enum_type: str, value: str, locale: Optional[str] = None) -> str:
+    """
+    Translate an enum value (convenience function).
+
+    Args:
+        enum_type: Enum type name
+        value: Enum value
+        locale: Target locale
+
+    Returns:
+        Translated enum display name
+
+    Examples:
+        t_enum("workspace_role", "manager")
+        t_enum("invite_status", "pending", "en")
+    """
+    service = get_translation_service()
+    return service.translate_enum(enum_type, value, locale)

api/app/locales/en/README.md

@@ -0,0 +1,26 @@
+# English Translation Files
+
+This directory contains English translation files.
+
+## File Structure
+
+- `common.json` - Common translations (success messages, actions, validation)
+- `auth.json` - Authentication module translations
+- `workspace.json` - Workspace module translations
+- `tenant.json` - Tenant module translations
+- `errors.json` - Error message translations
+- `enums.json` - Enum value translations
+
+## Translation File Format
+
+All translation files use JSON format and support nested structures.
+
+Example:
+```json
+{
+  "success": {
+    "created": "Created successfully",
+    "updated": "Updated successfully"
+  }
+}
+```

api/app/locales/en/auth.json

@@ -0,0 +1,55 @@
+{
+  "login": {
+    "success": "Login successful",
+    "failed": "Login failed",
+    "invalid_credentials": "Invalid username or password",
+    "account_locked": "Account has been locked",
+    "account_disabled": "Account has been disabled"
+  },
+  "logout": {
+    "success": "Logout successful",
+    "failed": "Logout failed"
+  },
+  "token": {
+    "refresh_success": "Token refreshed successfully",
+    "invalid": "Invalid token",
+    "expired": "Token has expired",
+    "blacklisted": "Token has been invalidated",
+    "invalid_refresh_token": "Invalid refresh token",
+    "refresh_token_blacklisted": "Refresh token has been invalidated"
+  },
+  "registration": {
+    "success": "Registration successful",
+    "failed": "Registration failed",
+    "email_exists": "Email already in use",
+    "username_exists": "Username already taken"
+  },
+  "password": {
+    "reset_success": "Password reset successful",
+    "reset_failed": "Password reset failed",
+    "change_success": "Password changed successfully",
+    "change_failed": "Password change failed",
+    "incorrect": "Incorrect password",
+    "too_weak": "Password is too weak",
+    "mismatch": "Passwords do not match"
+  },
+  "invite": {
+    "invalid": "Invalid or expired invite code",
+    "email_mismatch": "Invite email does not match login email",
+    "accept_success": "Invite accepted successfully",
+    "accept_failed": "Failed to accept invite",
+    "password_verification_failed": "Failed to accept invite, password verification error",
+    "bind_workspace_success": "Workspace bound successfully",
+    "bind_workspace_failed": "Failed to bind workspace"
+  },
+  "user": {
+    "not_found": "User not found",
+    "already_exists": "User already exists",
+    "created_with_invite": "User created successfully and joined workspace"
+  },
+  "session": {
+    "expired": "Session expired, please login again",
+    "invalid": "Invalid session",
+    "single_session_enabled": "Single sign-on enabled, other device sessions will be logged out"
+  }
+}

api/app/locales/en/common.json

@@ -0,0 +1,132 @@
+{
+  "success": {
+    "created": "Created successfully",
+    "updated": "Updated successfully",
+    "deleted": "Deleted successfully",
+    "retrieved": "Retrieved successfully",
+    "saved": "Saved successfully",
+    "uploaded": "Uploaded successfully",
+    "downloaded": "Downloaded successfully",
+    "sent": "Sent successfully",
+    "completed": "Completed",
+    "confirmed": "Confirmed",
+    "cancelled": "Cancelled",
+    "archived": "Archived",
+    "restored": "Restored"
+  },
+  "actions": {
+    "create": "Create",
+    "update": "Update",
+    "delete": "Delete",
+    "view": "View",
+    "edit": "Edit",
+    "save": "Save",
+    "cancel": "Cancel",
+    "confirm": "Confirm",
+    "submit": "Submit",
+    "upload": "Upload",
+    "download": "Download",
+    "send": "Send",
+    "search": "Search",
+    "filter": "Filter",
+    "sort": "Sort",
+    "export": "Export",
+    "import": "Import",
+    "refresh": "Refresh",
+    "reset": "Reset",
+    "back": "Back",
+    "next": "Next",
+    "previous": "Previous",
+    "finish": "Finish",
+    "close": "Close",
+    "open": "Open",
+    "archive": "Archive",
+    "restore": "Restore",
+    "duplicate": "Duplicate",
+    "share": "Share",
+    "invite": "Invite",
+    "remove": "Remove",
+    "add": "Add",
+    "select": "Select",
+    "clear": "Clear"
+  },
+  "validation": {
+    "required": "{field} is required",
+    "invalid_format": "{field} format is invalid",
+    "too_long": "{field} cannot exceed {max} characters",
+    "too_short": "{field} must be at least {min} characters",
+    "invalid_email": "Invalid email format",
+    "invalid_url": "Invalid URL format",
+    "invalid_phone": "Invalid phone number format",
+    "invalid_date": "Invalid date format",
+    "invalid_number": "Must be a valid number",
+    "out_of_range": "{field} must be between {min} and {max}",
+    "already_exists": "{field} already exists",
+    "not_found": "{field} not found",
+    "invalid_value": "Invalid value for {field}",
+    "password_mismatch": "Passwords do not match",
+    "weak_password": "Password is too weak, please use a stronger password",
+    "invalid_credentials": "Invalid username or password",
+    "unauthorized": "Unauthorized access",
+    "forbidden": "Permission denied",
+    "expired": "{field} has expired",
+    "invalid_token": "Invalid token",
+    "file_too_large": "File size cannot exceed {max}",
+    "invalid_file_type": "Unsupported file type",
+    "duplicate": "Duplicate {field}"
+  },
+  "status": {
+    "active": "Active",
+    "inactive": "Inactive",
+    "pending": "Pending",
+    "processing": "Processing",
+    "completed": "Completed",
+    "failed": "Failed",
+    "cancelled": "Cancelled",
+    "archived": "Archived",
+    "deleted": "Deleted",
+    "draft": "Draft",
+    "published": "Published",
+    "suspended": "Suspended",
+    "expired": "Expired"
+  },
+  "messages": {
+    "loading": "Loading...",
+    "saving": "Saving...",
+    "processing": "Processing...",
+    "uploading": "Uploading...",
+    "downloading": "Downloading...",
+    "no_data": "No data available",
+    "no_results": "No results found",
+    "confirm_delete": "Are you sure you want to delete? This action cannot be undone.",
+    "confirm_action": "Are you sure you want to perform this action?",
+    "operation_success": "Operation successful",
+    "operation_failed": "Operation failed",
+    "please_wait": "Please wait...",
+    "try_again": "Please try again",
+    "contact_support": "If the problem persists, please contact support"
+  },
+  "pagination": {
+    "page": "Page {page}",
+    "of": "of {total}",
+    "items": "{total} items",
+    "per_page": "{count} per page",
+    "showing": "Showing {from} to {to} of {total}",
+    "first": "First",
+    "last": "Last",
+    "next": "Next",
+    "previous": "Previous"
+  },
+  "time": {
+    "just_now": "Just now",
+    "minutes_ago": "{count} minutes ago",
+    "hours_ago": "{count} hours ago",
+    "days_ago": "{count} days ago",
+    "weeks_ago": "{count} weeks ago",
+    "months_ago": "{count} months ago",
+    "years_ago": "{count} years ago",
+    "today": "Today",
+    "yesterday": "Yesterday",
+    "tomorrow": "Tomorrow"
+  }
+}

api/app/locales/en/enums.json

@@ -0,0 +1,132 @@
+{
+  "workspace_role": {
+    "owner": "Owner",
+    "manager": "Manager",
+    "member": "Member",
+    "guest": "Guest"
+  },
+  "workspace_status": {
+    "active": "Active",
+    "inactive": "Inactive",
+    "archived": "Archived",
+    "suspended": "Suspended",
+    "deleted": "Deleted"
+  },
+  "invite_status": {
+    "pending": "Pending",
+    "accepted": "Accepted",
+    "rejected": "Rejected",
+    "revoked": "Revoked",
+    "expired": "Expired"
+  },
+  "user_status": {
+    "active": "Active",
+    "inactive": "Inactive",
+    "suspended": "Suspended",
+    "deleted": "Deleted",
+    "pending": "Pending"
+  },
+  "tenant_status": {
+    "active": "Active",
+    "inactive": "Inactive",
+    "suspended": "Suspended",
+    "expired": "Expired",
+    "trial": "Trial"
+  },
+  "file_status": {
+    "uploading": "Uploading",
+    "processing": "Processing",
+    "completed": "Completed",
+    "failed": "Failed",
+    "deleted": "Deleted"
+  },
+  "task_status": {
+    "pending": "Pending",
+    "running": "Running",
+    "completed": "Completed",
+    "failed": "Failed",
+    "cancelled": "Cancelled",
+    "paused": "Paused"
+  },
+  "priority": {
+    "low": "Low",
+    "medium": "Medium",
+    "high": "High",
+    "urgent": "Urgent"
+  },
+  "visibility": {
+    "public": "Public",
+    "private": "Private",
+    "internal": "Internal",
+    "shared": "Shared"
+  },
+  "permission": {
+    "read": "Read",
+    "write": "Write",
+    "delete": "Delete",
+    "admin": "Admin",
+    "owner": "Owner"
+  },
+  "notification_type": {
+    "info": "Info",
+    "warning": "Warning",
+    "error": "Error",
+    "success": "Success"
+  },
+  "language": {
+    "zh": "Chinese (Simplified)",
+    "en": "English",
+    "ja": "Japanese",
+    "ko": "Korean",
+    "fr": "French",
+    "de": "German",
+    "es": "Spanish"
+  },
+  "timezone": {
+    "utc": "UTC",
+    "asia_shanghai": "Asia/Shanghai",
+    "asia_tokyo": "Asia/Tokyo",
+    "america_new_york": "America/New_York",
+    "europe_london": "Europe/London"
+  },
+  "date_format": {
+    "short": "Short",
+    "medium": "Medium",
+    "long": "Long",
+    "full": "Full"
+  },
+  "sort_order": {
+    "asc": "Ascending",
+    "desc": "Descending"
+  },
+  "filter_operator": {
+    "equals": "Equals",
+    "not_equals": "Not Equals",
+    "contains": "Contains",
+    "not_contains": "Not Contains",
+    "starts_with": "Starts With",
+    "ends_with": "Ends With",
+    "greater_than": "Greater Than",
+    "less_than": "Less Than",
+    "greater_or_equal": "Greater or Equal",
+    "less_or_equal": "Less or Equal",
+    "in": "In",
+    "not_in": "Not In",
+    "is_null": "Is Null",
+    "is_not_null": "Is Not Null"
+  },
+  "log_level": {
+    "debug": "Debug",
+    "info": "Info",
+    "warning": "Warning",
+    "error": "Error",
+    "critical": "Critical"
+  },
+  "api_method": {
+    "get": "GET",
+    "post": "POST",
+    "put": "PUT",
+    "patch": "PATCH",
+    "delete": "DELETE"
+  }
+}

api/app/locales/en/errors.json

@@ -0,0 +1,138 @@
+{
+  "common": {
+    "internal_error": "Internal server error",
+    "network_error": "Network connection error",
+    "timeout": "Request timeout",
+    "service_unavailable": "Service temporarily unavailable",
+    "bad_request": "Bad request parameters",
+    "unauthorized": "Unauthorized access",
+    "forbidden": "Access forbidden",
+    "not_found": "Resource not found",
+    "method_not_allowed": "Method not allowed",
+    "conflict": "Resource conflict",
+    "too_many_requests": "Too many requests, please try again later",
+    "validation_failed": "Validation failed",
+    "database_error": "Database operation failed",
+    "file_operation_error": "File operation failed"
+  },
+  "auth": {
+    "invalid_credentials": "Invalid username or password",
+    "token_expired": "Session expired, please login again",
+    "token_invalid": "Invalid authentication token",
+    "token_missing": "Authentication token missing",
+    "unauthorized": "Unauthorized access",
+    "forbidden": "Permission denied",
+    "account_locked": "Account has been locked",
+    "account_disabled": "Account has been disabled",
+    "account_not_verified": "Account not verified",
+    "password_incorrect": "Incorrect password",
+    "password_too_weak": "Password is too weak",
+    "password_expired": "Password expired, please change it",
+    "email_not_verified": "Email not verified",
+    "phone_not_verified": "Phone number not verified",
+    "verification_code_invalid": "Invalid verification code",
+    "verification_code_expired": "Verification code expired",
+    "login_failed": "Login failed",
+    "logout_failed": "Logout failed",
+    "session_expired": "Session expired",
+    "already_logged_in": "Already logged in",
+    "not_logged_in": "Not logged in"
+  },
+  "user": {
+    "not_found": "User not found",
+    "already_exists": "User already exists",
+    "email_already_exists": "Email already in use",
+    "phone_already_exists": "Phone number already in use",
+    "username_already_exists": "Username already taken",
+    "invalid_email": "Invalid email format",
+    "invalid_phone": "Invalid phone number format",
+    "invalid_username": "Invalid username format",
+    "create_failed": "Failed to create user",
+    "update_failed": "Failed to update user",
+    "delete_failed": "Failed to delete user",
+    "cannot_delete_self": "Cannot delete yourself",
+    "cannot_update_self_role": "Cannot update your own role",
+    "profile_update_failed": "Failed to update profile",
+    "avatar_upload_failed": "Failed to upload avatar",
+    "password_change_failed": "Failed to change password",
+    "old_password_incorrect": "Old password is incorrect"
+  },
+  "workspace": {
+    "not_found": "Workspace not found",
+    "already_exists": "Workspace already exists",
+    "name_required": "Workspace name is required",
+    "name_too_long": "Workspace name is too long",
+    "create_failed": "Failed to create workspace",
+    "update_failed": "Failed to update workspace",
+    "delete_failed": "Failed to delete workspace",
+    "permission_denied": "Permission denied to access this workspace",
+    "not_member": "Not a workspace member",
+    "already_member": "Already a workspace member",
+    "member_limit_reached": "Member limit reached",
+    "cannot_leave_last_manager": "Cannot leave, you are the last manager",
+    "cannot_remove_last_manager": "Cannot remove the last manager",
+    "cannot_remove_self": "Cannot remove yourself",
+    "invite_not_found": "Invite not found",
+    "invite_expired": "Invite has expired",
+    "invite_already_accepted": "Invite already accepted",
+    "invite_already_revoked": "Invite already revoked",
+    "invite_send_failed": "Failed to send invite",
+    "archived": "Workspace is archived",
+    "suspended": "Workspace is suspended"
+  },
+  "tenant": {
+    "not_found": "Tenant not found",
+    "already_exists": "Tenant already exists",
+    "create_failed": "Failed to create tenant",
+    "update_failed": "Failed to update tenant",
+    "delete_failed": "Failed to delete tenant",
+    "suspended": "Tenant is suspended",
+    "expired": "Tenant has expired",
+    "license_invalid": "Invalid license",
+    "license_expired": "License has expired",
+    "quota_exceeded": "Quota exceeded"
+  },
+  "file": {
+    "not_found": "File not found",
+    "upload_failed": "File upload failed",
+    "download_failed": "File download failed",
+    "delete_failed": "File deletion failed",
+    "too_large": "File size exceeds limit",
+    "invalid_type": "Unsupported file type",
+    "invalid_format": "Invalid file format",
+    "corrupted": "File is corrupted",
+    "storage_full": "Storage is full",
+    "access_denied": "Access denied to this file"
+  },
+  "api": {
+    "rate_limit_exceeded": "API rate limit exceeded",
+    "quota_exceeded": "API quota exceeded",
+    "invalid_api_key": "Invalid API key",
+    "api_key_expired": "API key has expired",
+    "api_key_revoked": "API key has been revoked",
+    "endpoint_not_found": "API endpoint not found",
+    "method_not_allowed": "Method not allowed",
+    "invalid_request": "Invalid request",
+    "missing_parameter": "Missing required parameter: {param}",
+    "invalid_parameter": "Invalid parameter: {param}"
+  },
+  "database": {
+    "connection_failed": "Database connection failed",
+    "query_failed": "Database query failed",
+    "transaction_failed": "Database transaction failed",
+    "constraint_violation": "Data constraint violation",
+    "duplicate_key": "Duplicate data",
+    "foreign_key_violation": "Foreign key constraint violation",
+    "deadlock": "Database deadlock"
+  },
+  "validation": {
+    "invalid_input": "Invalid input data",
+    "missing_field": "Missing required field: {field}",
+    "invalid_field": "Invalid field: {field}",
+    "field_too_long": "Field too long: {field}",
+    "field_too_short": "Field too short: {field}",
+    "invalid_format": "Invalid format: {field}",
+    "invalid_value": "Invalid value: {field}",
+    "out_of_range": "Value out of range: {field}"
+  }
+}

api/app/locales/en/i18n.json

@@ -0,0 +1,27 @@
+{
+  "language": {
+    "not_found": "Language {locale} not found",
+    "already_exists": "Language {locale} already exists",
+    "add_instructions": "Language {locale} validated successfully. Please create translation files in {dir} directory to complete the addition.",
+    "update_instructions": "Language {locale} update validated successfully. Please update I18N_SUPPORTED_LANGUAGES environment variable to apply configuration changes."
+  },
+  "namespace": {
+    "not_found": "Namespace {namespace} not found in language {locale}"
+  },
+  "translation": {
+    "invalid_key_format": "Invalid translation key format: {key}. Should use format: namespace.key.subkey",
+    "update_instructions": "Translation {locale}/{key} update validated successfully. Please modify the corresponding JSON translation file to apply changes."
+  },
+  "reload": {
+    "disabled": "Translation hot reload is disabled. Please enable I18N_ENABLE_HOT_RELOAD in configuration.",
+    "success": "Translations reloaded successfully",
+    "failed": "Translation reload failed: {error}"
+  },
+  "metrics": {
+    "reset_success": "Performance metrics reset successfully"
+  },
+  "logs": {
+    "export_success": "Missing translations exported to: {file}",
+    "clear_success": "Missing translation logs cleared successfully"
+  }
+}

api/app/locales/en/tenant.json

@@ -0,0 +1,63 @@
+{
+  "info": {
+    "get_success": "Tenant information retrieved successfully",
+    "get_failed": "Failed to retrieve tenant information",
+    "update_success": "Tenant information updated successfully",
+    "update_failed": "Failed to update tenant information"
+  },
+  "create": {
+    "success": "Tenant created successfully",
+    "failed": "Failed to create tenant"
+  },
+  "delete": {
+    "success": "Tenant deleted successfully",
+    "failed": "Failed to delete tenant"
+  },
+  "status": {
+    "activate_success": "Tenant activated successfully",
+    "activate_failed": "Failed to activate tenant",
+    "deactivate_success": "Tenant deactivated successfully",
+    "deactivate_failed": "Failed to deactivate tenant"
+  },
+  "language": {
+    "get_success": "Tenant language configuration retrieved successfully",
+    "get_failed": "Failed to retrieve tenant language configuration",
+    "update_success": "Tenant language configuration updated successfully",
+    "update_failed": "Failed to update tenant language configuration",
+    "invalid_language": "Unsupported language code",
+    "default_not_in_supported": "Default language must be in the supported languages list"
+  },
+  "list": {
+    "get_success": "Tenant list retrieved successfully",
+    "get_failed": "Failed to retrieve tenant list"
+  },
+  "users": {
+    "list_success": "Tenant user list retrieved successfully",
+    "list_failed": "Failed to retrieve tenant user list",
+    "assign_success": "User assigned to tenant successfully",
+    "assign_failed": "Failed to assign user to tenant",
+    "remove_success": "User removed from tenant successfully",
+    "remove_failed": "Failed to remove user from tenant"
+  },
+  "statistics": {
+    "get_success": "Tenant statistics retrieved successfully",
+    "get_failed": "Failed to retrieve tenant statistics"
+  },
+  "validation": {
+    "name_required": "Tenant name is required",
+    "name_invalid": "Invalid tenant name format",
+    "name_too_long": "Tenant name cannot exceed {max} characters",
+    "description_too_long": "Tenant description cannot exceed {max} characters",
+    "language_code_invalid": "Invalid language code format",
+    "supported_languages_empty": "Supported languages list cannot be empty"
+  },
+  "errors": {
+    "not_found": "Tenant not found",
+    "already_exists": "Tenant name already exists",
+    "permission_denied": "Permission denied to access this tenant",
+    "has_users": "Cannot delete tenant, associated users exist",
+    "has_workspaces": "Cannot delete tenant, associated workspaces exist",
+    "already_active": "Tenant is already active",
+    "already_inactive": "Tenant is already inactive"
+  }
+}

api/app/locales/en/users.json

@@ -0,0 +1,72 @@
+{
+  "info": {
+    "get_success": "User information retrieved successfully",
+    "get_failed": "Failed to retrieve user information",
+    "update_success": "User information updated successfully",
+    "update_failed": "Failed to update user information"
+  },
+  "create": {
+    "success": "User created successfully",
+    "failed": "Failed to create user",
+    "superuser_success": "Superuser created successfully",
+    "superuser_failed": "Failed to create superuser"
+  },
+  "delete": {
+    "success": "User deleted successfully",
+    "failed": "Failed to delete user",
+    "deactivate_success": "User deactivated successfully",
+    "deactivate_failed": "Failed to deactivate user"
+  },
+  "activate": {
+    "success": "User activated successfully",
+    "failed": "Failed to activate user"
+  },
+  "language": {
+    "get_success": "Language preference retrieved successfully",
+    "get_failed": "Failed to retrieve language preference",
+    "update_success": "Language preference updated successfully",
+    "update_failed": "Failed to update language preference",
+    "invalid_language": "Unsupported language code",
+    "current": "Current language preference"
+  },
+  "email": {
+    "change_success": "Email changed successfully",
+    "change_failed": "Failed to change email",
+    "code_sent": "Verification code has been sent to your email",
+    "code_send_failed": "Failed to send verification code",
+    "code_invalid": "Invalid or expired verification code",
+    "already_exists": "Email already in use"
+  },
+  "list": {
+    "get_success": "User list retrieved successfully",
+    "get_failed": "Failed to retrieve user list",
+    "superusers_success": "Tenant superuser list retrieved successfully",
+    "superusers_failed": "Failed to retrieve tenant superuser list"
+  },
+  "validation": {
+    "username_required": "Username is required",
+    "username_invalid": "Invalid username format",
+    "username_too_long": "Username cannot exceed {max} characters",
+    "email_required": "Email is required",
+    "email_invalid": "Invalid email format",
+    "password_required": "Password is required",
+    "password_too_short": "Password must be at least {min} characters",
+    "password_too_long": "Password cannot exceed {max} characters",
+    "old_password_required": "Old password is required",
+    "new_password_required": "New password is required",
+    "verification_code_required": "Verification code is required",
+    "verification_code_invalid": "Invalid verification code format"
+  },
+  "errors": {
+    "not_found": "User not found",
+    "already_exists": "User already exists",
+    "permission_denied": "Permission denied to access this user",
+    "cannot_delete_self": "Cannot delete yourself",
+    "cannot_deactivate_self": "Cannot deactivate yourself",
+    "already_deactivated": "User is already deactivated",
+    "already_activated": "User is already activated",
+    "password_verification_failed": "Password verification failed",
+    "old_password_incorrect": "Old password is incorrect",
+    "same_as_old_password": "New password cannot be the same as old password"
+  }
+}

api/app/locales/en/workspace.json

@@ -0,0 +1,44 @@
+{
+  "list_retrieved": "Workspace list retrieved successfully",
+  "created": "Workspace created successfully",
+  "updated": "Workspace updated successfully",
+  "deleted": "Workspace deleted successfully",
+  "switched": "Workspace switched successfully",
+  "not_found": "Workspace not found or access denied",
+  "already_exists": "Workspace already exists",
+  "permission_denied": "No permission to access this workspace",
+  "name_required": "Workspace name is required",
+  "invalid_name": "Invalid workspace name format",
+  "members": {
+    "list_retrieved": "Workspace members list retrieved successfully",
+    "role_updated": "Member role updated successfully",
+    "deleted": "Member deleted successfully",
+    "not_found": "Member not found",
+    "cannot_remove_self": "Cannot remove yourself",
+    "cannot_remove_last_manager": "Cannot remove the last manager",
+    "already_member": "User is already a workspace member"
+  },
+  "invites": {
+    "created": "Invite created successfully",
+    "list_retrieved": "Invite list retrieved successfully",
+    "validated": "Invite validated successfully",
+    "revoked": "Invite revoked successfully",
+    "accepted": "Invite accepted",
+    "not_found": "Invite not found",
+    "expired": "Invite has expired",
+    "already_used": "Invite has already been used",
+    "invalid_token": "Invalid invite token",
+    "email_required": "Email address is required",
+    "invalid_email": "Invalid email address format"
+  },
+  "storage": {
+    "type_retrieved": "Storage type retrieved successfully",
+    "type_updated": "Storage type updated successfully",
+    "invalid_type": "Invalid storage type"
+  },
+  "models": {
+    "config_retrieved": "Model configuration retrieved successfully",
+    "config_updated": "Model configuration updated successfully",
+    "invalid_config": "Invalid model configuration"
+  }
+}

api/app/locales/zh/README.md

@@ -0,0 +1,26 @@
+# 中文翻译文件
+
+此目录包含中文（简体）的翻译文件。
+
+## 文件结构
+
+- `common.json` - 通用翻译（成功消息、操作、验证）
+- `auth.json` - 认证模块翻译
+- `workspace.json` - 工作空间模块翻译
+- `tenant.json` - 租户模块翻译
+- `errors.json` - 错误消息翻译
+- `enums.json` - 枚举值翻译
+
+## 翻译文件格式
+
+所有翻译文件使用 JSON 格式，支持嵌套结构。
+
+示例：
+```json
+{
+  "success": {
+    "created": "创建成功",
+    "updated": "更新成功"
+  }
+}
+```

api/app/locales/zh/auth.json

@@ -0,0 +1,55 @@
+{
+  "login": {
+    "success": "登录成功",
+    "failed": "登录失败",
+    "invalid_credentials": "用户名或密码错误",
+    "account_locked": "账户已被锁定",
+    "account_disabled": "账户已被禁用"
+  },
+  "logout": {
+    "success": "登出成功",
+    "failed": "登出失败"
+  },
+  "token": {
+    "refresh_success": "token刷新成功",
+    "invalid": "无效的token",
+    "expired": "token已过期",
+    "blacklisted": "token已失效",
+    "invalid_refresh_token": "无效的refresh token",
+    "refresh_token_blacklisted": "Refresh token已失效"
+  },
+  "registration": {
+    "success": "注册成功",
+    "failed": "注册失败",
+    "email_exists": "邮箱已被使用",
+    "username_exists": "用户名已被使用"
+  },
+  "password": {
+    "reset_success": "密码重置成功",
+    "reset_failed": "密码重置失败",
+    "change_success": "密码修改成功",
+    "change_failed": "密码修改失败",
+    "incorrect": "密码错误",
+    "too_weak": "密码强度不够",
+    "mismatch": "两次输入的密码不一致"
+  },
+  "invite": {
+    "invalid": "邀请码无效或已过期",
+    "email_mismatch": "邀请邮箱与登录邮箱不匹配",
+    "accept_success": "接受邀请成功",
+    "accept_failed": "接受邀请失败",
+    "password_verification_failed": "接受邀请失败，密码验证错误",
+    "bind_workspace_success": "绑定工作空间成功",
+    "bind_workspace_failed": "绑定工作空间失败"
+  },
+  "user": {
+    "not_found": "用户不存在",
+    "already_exists": "用户已存在",
+    "created_with_invite": "用户创建成功并已加入工作空间"
+  },
+  "session": {
+    "expired": "会话已过期，请重新登录",
+    "invalid": "无效的会话",
+    "single_session_enabled": "单点登录已启用，其他设备的登录将被注销"
+  }
+}

api/app/locales/zh/common.json

@@ -0,0 +1,132 @@
+{
+  "success": {
+    "created": "创建成功",
+    "updated": "更新成功",
+    "deleted": "删除成功",
+    "retrieved": "获取成功",
+    "saved": "保存成功",
+    "uploaded": "上传成功",
+    "downloaded": "下载成功",
+    "sent": "发送成功",
+    "completed": "完成",
+    "confirmed": "已确认",
+    "cancelled": "已取消",
+    "archived": "已归档",
+    "restored": "已恢复"
+  },
+  "actions": {
+    "create": "创建",
+    "update": "更新",
+    "delete": "删除",
+    "view": "查看",
+    "edit": "编辑",
+    "save": "保存",
+    "cancel": "取消",
+    "confirm": "确认",
+    "submit": "提交",
+    "upload": "上传",
+    "download": "下载",
+    "send": "发送",
+    "search": "搜索",
+    "filter": "筛选",
+    "sort": "排序",
+    "export": "导出",
+    "import": "导入",
+    "refresh": "刷新",
+    "reset": "重置",
+    "back": "返回",
+    "next": "下一步",
+    "previous": "上一步",
+    "finish": "完成",
+    "close": "关闭",
+    "open": "打开",
+    "archive": "归档",
+    "restore": "恢复",
+    "duplicate": "复制",
+    "share": "分享",
+    "invite": "邀请",
+    "remove": "移除",
+    "add": "添加",
+    "select": "选择",
+    "clear": "清除"
+  },
+  "validation": {
+    "required": "{field}不能为空",
+    "invalid_format": "{field}格式不正确",
+    "too_long": "{field}长度不能超过{max}个字符",
+    "too_short": "{field}长度不能少于{min}个字符",
+    "invalid_email": "邮箱格式不正确",
+    "invalid_url": "URL格式不正确",
+    "invalid_phone": "手机号格式不正确",
+    "invalid_date": "日期格式不正确",
+    "invalid_number": "必须是有效的数字",
+    "out_of_range": "{field}必须在{min}和{max}之间",
+    "already_exists": "{field}已存在",
+    "not_found": "{field}不存在",
+    "invalid_value": "{field}的值无效",
+    "password_mismatch": "两次输入的密码不一致",
+    "weak_password": "密码强度不够，请使用更复杂的密码",
+    "invalid_credentials": "用户名或密码错误",
+    "unauthorized": "未授权访问",
+    "forbidden": "没有权限执行此操作",
+    "expired": "{field}已过期",
+    "invalid_token": "无效的令牌",
+    "file_too_large": "文件大小不能超过{max}",
+    "invalid_file_type": "不支持的文件类型",
+    "duplicate": "重复的{field}"
+  },
+  "status": {
+    "active": "活跃",
+    "inactive": "未激活",
+    "pending": "待处理",
+    "processing": "处理中",
+    "completed": "已完成",
+    "failed": "失败",
+    "cancelled": "已取消",
+    "archived": "已归档",
+    "deleted": "已删除",
+    "draft": "草稿",
+    "published": "已发布",
+    "suspended": "已暂停",
+    "expired": "已过期"
+  },
+  "messages": {
+    "loading": "加载中...",
+    "saving": "保存中...",
+    "processing": "处理中...",
+    "uploading": "上传中...",
+    "downloading": "下载中...",
+    "no_data": "暂无数据",
+    "no_results": "没有找到结果",
+    "confirm_delete": "确定要删除吗？此操作不可恢复。",
+    "confirm_action": "确定要执行此操作吗？",
+    "operation_success": "操作成功",
+    "operation_failed": "操作失败",
+    "please_wait": "请稍候...",
+    "try_again": "请重试",
+    "contact_support": "如果问题持续，请联系技术支持"
+  },
+  "pagination": {
+    "page": "第{page}页",
+    "of": "共{total}页",
+    "items": "共{total}条",
+    "per_page": "每页{count}条",
+    "showing": "显示第{from}到第{to}条，共{total}条",
+    "first": "首页",
+    "last": "末页",
+    "next": "下一页",
+    "previous": "上一页"
+  },
+  "time": {
+    "just_now": "刚刚",
+    "minutes_ago": "{count}分钟前",
+    "hours_ago": "{count}小时前",
+    "days_ago": "{count}天前",
+    "weeks_ago": "{count}周前",
+    "months_ago": "{count}个月前",
+    "years_ago": "{count}年前",
+    "today": "今天",
+    "yesterday": "昨天",
+    "tomorrow": "明天"
+  }
+}

api/app/locales/zh/enums.json

@@ -0,0 +1,132 @@
+{
+  "workspace_role": {
+    "owner": "所有者",
+    "manager": "管理员",
+    "member": "成员",
+    "guest": "访客"
+  },
+  "workspace_status": {
+    "active": "活跃",
+    "inactive": "未激活",
+    "archived": "已归档",
+    "suspended": "已暂停",
+    "deleted": "已删除"
+  },
+  "invite_status": {
+    "pending": "待处理",
+    "accepted": "已接受",
+    "rejected": "已拒绝",
+    "revoked": "已撤销",
+    "expired": "已过期"
+  },
+  "user_status": {
+    "active": "活跃",
+    "inactive": "未激活",
+    "suspended": "已暂停",
+    "deleted": "已删除",
+    "pending": "待激活"
+  },
+  "tenant_status": {
+    "active": "活跃",
+    "inactive": "未激活",
+    "suspended": "已暂停",
+    "expired": "已过期",
+    "trial": "试用中"
+  },
+  "file_status": {
+    "uploading": "上传中",
+    "processing": "处理中",
+    "completed": "已完成",
+    "failed": "失败",
+    "deleted": "已删除"
+  },
+  "task_status": {
+    "pending": "待处理",
+    "running": "运行中",
+    "completed": "已完成",
+    "failed": "失败",
+    "cancelled": "已取消",
+    "paused": "已暂停"
+  },
+  "priority": {
+    "low": "低",
+    "medium": "中",
+    "high": "高",
+    "urgent": "紧急"
+  },
+  "visibility": {
+    "public": "公开",
+    "private": "私有",
+    "internal": "内部",
+    "shared": "共享"
+  },
+  "permission": {
+    "read": "读取",
+    "write": "写入",
+    "delete": "删除",
+    "admin": "管理",
+    "owner": "所有者"
+  },
+  "notification_type": {
+    "info": "信息",
+    "warning": "警告",
+    "error": "错误",
+    "success": "成功"
+  },
+  "language": {
+    "zh": "中文（简体）",
+    "en": "English",
+    "ja": "日本語",
+    "ko": "한국어",
+    "fr": "Français",
+    "de": "Deutsch",
+    "es": "Español"
+  },
+  "timezone": {
+    "utc": "UTC",
+    "asia_shanghai": "亚洲/上海",
+    "asia_tokyo": "亚洲/东京",
+    "america_new_york": "美洲/纽约",
+    "europe_london": "欧洲/伦敦"
+  },
+  "date_format": {
+    "short": "短日期",
+    "medium": "中等日期",
+    "long": "长日期",
+    "full": "完整日期"
+  },
+  "sort_order": {
+    "asc": "升序",
+    "desc": "降序"
+  },
+  "filter_operator": {
+    "equals": "等于",
+    "not_equals": "不等于",
+    "contains": "包含",
+    "not_contains": "不包含",
+    "starts_with": "开始于",
+    "ends_with": "结束于",
+    "greater_than": "大于",
+    "less_than": "小于",
+    "greater_or_equal": "大于等于",
+    "less_or_equal": "小于等于",
+    "in": "在列表中",
+    "not_in": "不在列表中",
+    "is_null": "为空",
+    "is_not_null": "不为空"
+  },
+  "log_level": {
+    "debug": "调试",
+    "info": "信息",
+    "warning": "警告",
+    "error": "错误",
+    "critical": "严重"
+  },
+  "api_method": {
+    "get": "GET",
+    "post": "POST",
+    "put": "PUT",
+    "patch": "PATCH",
+    "delete": "DELETE"
+  }
+}

api/app/locales/zh/errors.json

@@ -0,0 +1,138 @@
+{
+  "common": {
+    "internal_error": "服务器内部错误",
+    "network_error": "网络连接错误",
+    "timeout": "请求超时",
+    "service_unavailable": "服务暂时不可用",
+    "bad_request": "请求参数错误",
+    "unauthorized": "未授权访问",
+    "forbidden": "没有权限访问",
+    "not_found": "请求的资源不存在",
+    "method_not_allowed": "不支持的请求方法",
+    "conflict": "资源冲突",
+    "too_many_requests": "请求过于频繁，请稍后再试",
+    "validation_failed": "数据验证失败",
+    "database_error": "数据库操作失败",
+    "file_operation_error": "文件操作失败"
+  },
+  "auth": {
+    "invalid_credentials": "用户名或密码错误",
+    "token_expired": "登录已过期，请重新登录",
+    "token_invalid": "无效的登录令牌",
+    "token_missing": "缺少登录令牌",
+    "unauthorized": "未授权访问",
+    "forbidden": "没有权限执行此操作",
+    "account_locked": "账户已被锁定",
+    "account_disabled": "账户已被禁用",
+    "account_not_verified": "账户未验证",
+    "password_incorrect": "密码错误",
+    "password_too_weak": "密码强度不够",
+    "password_expired": "密码已过期，请修改密码",
+    "email_not_verified": "邮箱未验证",
+    "phone_not_verified": "手机号未验证",
+    "verification_code_invalid": "验证码无效",
+    "verification_code_expired": "验证码已过期",
+    "login_failed": "登录失败",
+    "logout_failed": "登出失败",
+    "session_expired": "会话已过期",
+    "already_logged_in": "已经登录",
+    "not_logged_in": "未登录"
+  },
+  "user": {
+    "not_found": "用户不存在",
+    "already_exists": "用户已存在",
+    "email_already_exists": "邮箱已被使用",
+    "phone_already_exists": "手机号已被使用",
+    "username_already_exists": "用户名已被使用",
+    "invalid_email": "邮箱格式不正确",
+    "invalid_phone": "手机号格式不正确",
+    "invalid_username": "用户名格式不正确",
+    "create_failed": "创建用户失败",
+    "update_failed": "更新用户失败",
+    "delete_failed": "删除用户失败",
+    "cannot_delete_self": "不能删除自己",
+    "cannot_update_self_role": "不能修改自己的角色",
+    "profile_update_failed": "更新个人资料失败",
+    "avatar_upload_failed": "上传头像失败",
+    "password_change_failed": "修改密码失败",
+    "old_password_incorrect": "原密码错误"
+  },
+  "workspace": {
+    "not_found": "工作空间不存在",
+    "already_exists": "工作空间已存在",
+    "name_required": "工作空间名称不能为空",
+    "name_too_long": "工作空间名称过长",
+    "create_failed": "创建工作空间失败",
+    "update_failed": "更新工作空间失败",
+    "delete_failed": "删除工作空间失败",
+    "permission_denied": "没有权限访问此工作空间",
+    "not_member": "不是工作空间成员",
+    "already_member": "已经是工作空间成员",
+    "member_limit_reached": "成员数量已达上限",
+    "cannot_leave_last_manager": "不能离开，您是最后一个管理员",
+    "cannot_remove_last_manager": "不能移除最后一个管理员",
+    "cannot_remove_self": "不能移除自己",
+    "invite_not_found": "邀请不存在",
+    "invite_expired": "邀请已过期",
+    "invite_already_accepted": "邀请已被接受",
+    "invite_already_revoked": "邀请已被撤销",
+    "invite_send_failed": "发送邀请失败",
+    "archived": "工作空间已归档",
+    "suspended": "工作空间已暂停"
+  },
+  "tenant": {
+    "not_found": "租户不存在",
+    "already_exists": "租户已存在",
+    "create_failed": "创建租户失败",
+    "update_failed": "更新租户失败",
+    "delete_failed": "删除租户失败",
+    "suspended": "租户已暂停",
+    "expired": "租户已过期",
+    "license_invalid": "许可证无效",
+    "license_expired": "许可证已过期",
+    "quota_exceeded": "配额已超限"
+  },
+  "file": {
+    "not_found": "文件不存在",
+    "upload_failed": "文件上传失败",
+    "download_failed": "文件下载失败",
+    "delete_failed": "文件删除失败",
+    "too_large": "文件大小超过限制",
+    "invalid_type": "不支持的文件类型",
+    "invalid_format": "文件格式不正确",
+    "corrupted": "文件已损坏",
+    "storage_full": "存储空间已满",
+    "access_denied": "没有权限访问此文件"
+  },
+  "api": {
+    "rate_limit_exceeded": "API调用频率超限",
+    "quota_exceeded": "API调用配额已用完",
+    "invalid_api_key": "无效的API密钥",
+    "api_key_expired": "API密钥已过期",
+    "api_key_revoked": "API密钥已被撤销",
+    "endpoint_not_found": "API端点不存在",
+    "method_not_allowed": "不支持的请求方法",
+    "invalid_request": "无效的请求",
+    "missing_parameter": "缺少必需参数：{param}",
+    "invalid_parameter": "参数无效：{param}"
+  },
+  "database": {
+    "connection_failed": "数据库连接失败",
+    "query_failed": "数据库查询失败",
+    "transaction_failed": "数据库事务失败",
+    "constraint_violation": "数据约束冲突",
+    "duplicate_key": "数据重复",
+    "foreign_key_violation": "外键约束冲突",
+    "deadlock": "数据库死锁"
+  },
+  "validation": {
+    "invalid_input": "输入数据无效",
+    "missing_field": "缺少必需字段：{field}",
+    "invalid_field": "字段无效：{field}",
+    "field_too_long": "字段过长：{field}",
+    "field_too_short": "字段过短：{field}",
+    "invalid_format": "格式不正确：{field}",
+    "invalid_value": "值无效：{field}",
+    "out_of_range": "值超出范围：{field}"
+  }
+}

api/app/locales/zh/i18n.json

@@ -0,0 +1,27 @@
+{
+  "language": {
+    "not_found": "语言 {locale} 不存在",
+    "already_exists": "语言 {locale} 已存在",
+    "add_instructions": "语言 {locale} 验证成功。请在 {dir} 目录下创建翻译文件以完成添加。",
+    "update_instructions": "语言 {locale} 更新验证成功。请更新环境变量 I18N_SUPPORTED_LANGUAGES 以应用配置更改。"
+  },
+  "namespace": {
+    "not_found": "命名空间 {namespace} 在语言 {locale} 中不存在"
+  },
+  "translation": {
+    "invalid_key_format": "翻译键格式无效: {key}。应使用格式: namespace.key.subkey",
+    "update_instructions": "翻译 {locale}/{key} 更新验证成功。请修改对应的 JSON 翻译文件以应用更改。"
+  },
+  "reload": {
+    "disabled": "翻译热重载功能已禁用。请在配置中启用 I18N_ENABLE_HOT_RELOAD。",
+    "success": "翻译重载成功",
+    "failed": "翻译重载失败: {error}"
+  },
+  "metrics": {
+    "reset_success": "性能指标已重置"
+  },
+  "logs": {
+    "export_success": "缺失翻译已导出到: {file}",
+    "clear_success": "缺失翻译日志已清除"
+  }
+}

api/app/locales/zh/tenant.json

@@ -0,0 +1,63 @@
+{
+  "info": {
+    "get_success": "租户信息获取成功",
+    "get_failed": "租户信息获取失败",
+    "update_success": "租户信息更新成功",
+    "update_failed": "租户信息更新失败"
+  },
+  "create": {
+    "success": "租户创建成功",
+    "failed": "租户创建失败"
+  },
+  "delete": {
+    "success": "租户删除成功",
+    "failed": "租户删除失败"
+  },
+  "status": {
+    "activate_success": "租户启用成功",
+    "activate_failed": "租户启用失败",
+    "deactivate_success": "租户禁用成功",
+    "deactivate_failed": "租户禁用失败"
+  },
+  "language": {
+    "get_success": "租户语言配置获取成功",
+    "get_failed": "租户语言配置获取失败",
+    "update_success": "租户语言配置更新成功",
+    "update_failed": "租户语言配置更新失败",
+    "invalid_language": "不支持的语言代码",
+    "default_not_in_supported": "默认语言必须在支持的语言列表中"
+  },
+  "list": {
+    "get_success": "租户列表获取成功",
+    "get_failed": "租户列表获取失败"
+  },
+  "users": {
+    "list_success": "租户用户列表获取成功",
+    "list_failed": "租户用户列表获取失败",
+    "assign_success": "用户分配到租户成功",
+    "assign_failed": "用户分配到租户失败",
+    "remove_success": "用户从租户移除成功",
+    "remove_failed": "用户从租户移除失败"
+  },
+  "statistics": {
+    "get_success": "租户统计信息获取成功",
+    "get_failed": "租户统计信息获取失败"
+  },
+  "validation": {
+    "name_required": "租户名称不能为空",
+    "name_invalid": "租户名称格式不正确",
+    "name_too_long": "租户名称长度不能超过{max}个字符",
+    "description_too_long": "租户描述长度不能超过{max}个字符",
+    "language_code_invalid": "语言代码格式不正确",
+    "supported_languages_empty": "支持的语言列表不能为空"
+  },
+  "errors": {
+    "not_found": "租户不存在",
+    "already_exists": "租户名称已存在",
+    "permission_denied": "没有权限访问此租户",
+    "has_users": "无法删除租户，存在关联的用户",
+    "has_workspaces": "无法删除租户，存在关联的工作空间",
+    "already_active": "租户已处于激活状态",
+    "already_inactive": "租户已处于禁用状态"
+  }
+}

api/app/locales/zh/users.json

@@ -0,0 +1,72 @@
+{
+  "info": {
+    "get_success": "用户信息获取成功",
+    "get_failed": "用户信息获取失败",
+    "update_success": "用户信息更新成功",
+    "update_failed": "用户信息更新失败"
+  },
+  "create": {
+    "success": "用户创建成功",
+    "failed": "用户创建失败",
+    "superuser_success": "超级管理员创建成功",
+    "superuser_failed": "超级管理员创建失败"
+  },
+  "delete": {
+    "success": "用户删除成功",
+    "failed": "用户删除失败",
+    "deactivate_success": "用户停用成功",
+    "deactivate_failed": "用户停用失败"
+  },
+  "activate": {
+    "success": "用户激活成功",
+    "failed": "用户激活失败"
+  },
+  "language": {
+    "get_success": "语言偏好获取成功",
+    "get_failed": "语言偏好获取失败",
+    "update_success": "语言偏好更新成功",
+    "update_failed": "语言偏好更新失败",
+    "invalid_language": "不支持的语言代码",
+    "current": "当前语言偏好"
+  },
+  "email": {
+    "change_success": "邮箱修改成功",
+    "change_failed": "邮箱修改失败",
+    "code_sent": "验证码已发送到您的邮箱，请查收",
+    "code_send_failed": "验证码发送失败",
+    "code_invalid": "验证码无效或已过期",
+    "already_exists": "该邮箱已被使用"
+  },
+  "list": {
+    "get_success": "用户列表获取成功",
+    "get_failed": "用户列表获取失败",
+    "superusers_success": "租户超管列表获取成功",
+    "superusers_failed": "租户超管列表获取失败"
+  },
+  "validation": {
+    "username_required": "用户名不能为空",
+    "username_invalid": "用户名格式不正确",
+    "username_too_long": "用户名长度不能超过{max}个字符",
+    "email_required": "邮箱不能为空",
+    "email_invalid": "邮箱格式不正确",
+    "password_required": "密码不能为空",
+    "password_too_short": "密码长度不能少于{min}个字符",
+    "password_too_long": "密码长度不能超过{max}个字符",
+    "old_password_required": "旧密码不能为空",
+    "new_password_required": "新密码不能为空",
+    "verification_code_required": "验证码不能为空",
+    "verification_code_invalid": "验证码格式不正确"
+  },
+  "errors": {
+    "not_found": "用户不存在",
+    "already_exists": "用户已存在",
+    "permission_denied": "没有权限访问此用户",
+    "cannot_delete_self": "不能删除自己",
+    "cannot_deactivate_self": "不能停用自己",
+    "already_deactivated": "用户已被停用",
+    "already_activated": "用户已处于激活状态",
+    "password_verification_failed": "密码验证失败",
+    "old_password_incorrect": "旧密码不正确",
+    "same_as_old_password": "新密码不能与旧密码相同"
+  }
+}

api/app/locales/zh/workspace.json

@@ -0,0 +1,44 @@
+{
+  "list_retrieved": "工作空间列表获取成功",
+  "created": "工作空间创建成功",
+  "updated": "工作空间更新成功",
+  "deleted": "工作空间删除成功",
+  "switched": "工作空间切换成功",
+  "not_found": "工作空间不存在或无权访问",
+  "already_exists": "工作空间已存在",
+  "permission_denied": "没有权限访问此工作空间",
+  "name_required": "工作空间名称不能为空",
+  "invalid_name": "工作空间名称格式不正确",
+  "members": {
+    "list_retrieved": "工作空间成员列表获取成功",
+    "role_updated": "成员角色更新成功",
+    "deleted": "成员删除成功",
+    "not_found": "成员不存在",
+    "cannot_remove_self": "不能删除自己",
+    "cannot_remove_last_manager": "不能删除最后一个管理员",
+    "already_member": "用户已经是工作空间成员"
+  },
+  "invites": {
+    "created": "邀请创建成功",
+    "list_retrieved": "邀请列表获取成功",
+    "validated": "邀请验证成功",
+    "revoked": "邀请撤销成功",
+    "accepted": "邀请已接受",
+    "not_found": "邀请不存在",
+    "expired": "邀请已过期",
+    "already_used": "邀请已被使用",
+    "invalid_token": "无效的邀请令牌",
+    "email_required": "邮箱地址不能为空",
+    "invalid_email": "邮箱地址格式不正确"
+  },
+  "storage": {
+    "type_retrieved": "存储类型获取成功",
+    "type_updated": "存储类型更新成功",
+    "invalid_type": "无效的存储类型"
+  },
+  "models": {
+    "config_retrieved": "模型配置获取成功",
+    "config_updated": "模型配置更新成功",
+    "invalid_config": "无效的模型配置"
+  }
+}

api/app/main.py

@@ -92,6 +92,10 @@ app.add_middleware(
     allow_headers=["*"],
 )
 
+# Add i18n language detection middleware
+from app.i18n.middleware import LanguageMiddleware
+app.add_middleware(LanguageMiddleware)
+
 logger.info("FastAPI应用程序启动")
 
 
@@ -129,6 +133,11 @@ from app.core.exceptions import (
 from app.core.sensitive_filter import SensitiveDataFilter
 import traceback
 
+# Import i18n exception support
+from app.i18n.exceptions import I18nException
+from app.i18n.service import get_translation_service
+from pydantic import ValidationError as PydanticValidationError
+
 
 # 处理验证异常
 @app.exception_handler(ValidationException)
@@ -156,6 +165,131 @@ async def validation_exception_handler(request: Request, exc: ValidationExceptio
     )
 
 
+# 处理 i18n 异常（国际化异常）
+@app.exception_handler(I18nException)
+async def i18n_exception_handler(request: Request, exc: I18nException):
+    """
+    处理国际化异常
+    
+    I18nException 已经自动翻译了错误消息，直接返回即可
+    """
+    # 获取当前语言
+    language = getattr(request.state, "language", settings.I18N_DEFAULT_LANGUAGE)
+    
+    # 获取异常详情（已经包含翻译后的消息）
+    detail = exc.detail
+    
+    # 过滤敏感信息
+    if isinstance(detail, dict):
+        filtered_message = SensitiveDataFilter.filter_string(detail.get("message", ""))
+        filtered_detail = {
+            **detail,
+            "message": filtered_message
+        }
+    else:
+        filtered_detail = SensitiveDataFilter.filter_string(str(detail))
+    
+    logger.warning(
+        f"I18n exception: {exc.error_key}",
+        extra={
+            "path": request.url.path,
+            "method": request.method,
+            "error_code": exc.error_code,
+            "error_key": exc.error_key,
+            "language": language,
+            "status_code": exc.status_code,
+            "params": exc.params
+        }
+    )
+    
+    return JSONResponse(
+        status_code=exc.status_code,
+        content={
+            "success": False,
+            **filtered_detail
+        },
+        headers=exc.headers
+    )
+
+
+# 处理 Pydantic 验证错误（国际化支持）
+@app.exception_handler(PydanticValidationError)
+async def pydantic_validation_exception_handler(request: Request, exc: PydanticValidationError):
+    """
+    处理 Pydantic 验证错误，支持国际化
+    """
+    # 获取当前语言
+    language = getattr(request.state, "language", settings.I18N_DEFAULT_LANGUAGE)
+    
+    # 获取翻译服务
+    translation_service = get_translation_service()
+    
+    # 翻译验证错误消息
+    errors = []
+    for error in exc.errors():
+        field = ".".join(str(loc) for loc in error["loc"])
+        error_type = error["type"]
+        
+        # 尝试翻译错误消息
+        if error_type == "value_error.missing":
+            message = translation_service.translate(
+                "errors.validation.missing_field",
+                language,
+                field=field
+            )
+        elif error_type == "value_error.any_str.max_length":
+            message = translation_service.translate(
+                "errors.validation.field_too_long",
+                language,
+                field=field
+            )
+        elif error_type == "value_error.any_str.min_length":
+            message = translation_service.translate(
+                "errors.validation.field_too_short",
+                language,
+                field=field
+            )
+        else:
+            # 使用通用验证错误消息
+            message = translation_service.translate(
+                "errors.validation.invalid_field",
+                language,
+                field=field
+            )
+        
+        errors.append({
+            "field": field,
+            "message": message,
+            "type": error_type
+        })
+    
+    # 翻译主错误消息
+    main_message = translation_service.translate(
+        "errors.common.validation_failed",
+        language
+    )
+    
+    logger.warning(
+        f"Pydantic validation error: {len(errors)} errors",
+        extra={
+            "path": request.url.path,
+            "method": request.method,
+            "language": language,
+            "errors": errors
+        }
+    )
+    
+    return JSONResponse(
+        status_code=422,
+        content={
+            "success": False,
+            "error_code": "VALIDATION_FAILED",
+            "message": main_message,
+            "errors": errors
+        }
+    )
+
+
 # 处理资源不存在异常
 @app.exception_handler(ResourceNotFoundException)
 async def not_found_exception_handler(request: Request, exc: ResourceNotFoundException):
@@ -354,31 +488,66 @@ async def business_exception_handler(request: Request, exc: BusinessException):
     )
 
 
-# 统一异常处理：将HTTPException转换为统一响应结构
+# 统一异常处理：将HTTPException转换为统一响应结构（支持国际化）
 @app.exception_handler(HTTPException)
 async def http_exception_handler(request: Request, exc: HTTPException):
-    """处理HTTP异常"""
-    # 过滤敏感信息
-    filtered_detail = SensitiveDataFilter.filter_string(str(exc.detail))
-
+    """处理HTTP异常，支持国际化"""
+    # 获取当前语言
+    language = getattr(request.state, "language", settings.I18N_DEFAULT_LANGUAGE)
+    
+    # 获取翻译服务
+    translation_service = get_translation_service()
+    
+    # 尝试翻译标准HTTP错误
+    error_key_map = {
+        400: "errors.common.bad_request",
+        401: "errors.common.unauthorized",
+        403: "errors.common.forbidden",
+        404: "errors.common.not_found",
+        405: "errors.common.method_not_allowed",
+        409: "errors.common.conflict",
+        422: "errors.common.validation_failed",
+        429: "errors.common.too_many_requests",
+        500: "errors.common.internal_error",
+        503: "errors.common.service_unavailable",
+    }
+    
+    # 如果有对应的翻译键，使用翻译
+    if exc.status_code in error_key_map:
+        translated_message = translation_service.translate(
+            error_key_map[exc.status_code],
+            language
+        )
+    else:
+        # 否则过滤原始消息
+        translated_message = SensitiveDataFilter.filter_string(str(exc.detail))
+    
     logger.warning(
-        f"HTTP exception: {filtered_detail}",
+        f"HTTP exception: {translated_message}",
         extra={
             "path": request.url.path,
             "method": request.method,
-            "status_code": exc.status_code
+            "status_code": exc.status_code,
+            "language": language
         }
     )
+    
     return JSONResponse(
         status_code=exc.status_code,
-        content=fail(code=exc.status_code, msg=filtered_detail, error=filtered_detail)
+        content=fail(code=exc.status_code, msg=translated_message, error=translated_message)
     )
 
 
-# 捕获未处理的异常，返回统一错误结构
+# 捕获未处理的异常，返回统一错误结构（支持国际化）
 @app.exception_handler(Exception)
 async def unhandled_exception_handler(request: Request, exc: Exception):
-    """处理未捕获的异常"""
+    """处理未捕获的异常，支持国际化"""
+    # 获取当前语言
+    language = getattr(request.state, "language", settings.I18N_DEFAULT_LANGUAGE)
+    
+    # 获取翻译服务
+    translation_service = get_translation_service()
+    
     # 记录完整的堆栈跟踪（日志过滤器会自动过滤敏感信息）
     logger.error(
         f"Unhandled exception: {exc}",
@@ -386,6 +555,7 @@ async def unhandled_exception_handler(request: Request, exc: Exception):
             "path": request.url.path,
             "method": request.method,
             "exception_type": type(exc).__name__,
+            "language": language,
             "traceback": traceback.format_exc()
         },
         exc_info=True
@@ -394,7 +564,11 @@ async def unhandled_exception_handler(request: Request, exc: Exception):
     # 生产环境隐藏详细错误信息
     environment = os.getenv("ENVIRONMENT", "development")
     if environment == "production":
-        message = "服务器内部错误，请稍后重试"
+        # 使用翻译的通用错误消息
+        message = translation_service.translate(
+            "errors.common.internal_error",
+            language
+        )
     else:
         # 开发环境也要过滤敏感信息
         message = SensitiveDataFilter.filter_string(str(exc))

api/app/models/tenant_model.py

@@ -1,7 +1,7 @@
 import datetime
 import uuid
-from sqlalchemy import Column, String, DateTime, Boolean
-from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy import Column, String, DateTime, Boolean, text
+from sqlalchemy.dialects.postgresql import UUID, ARRAY
 from sqlalchemy.orm import relationship
 from app.db import Base
 
@@ -20,6 +20,10 @@ class Tenants(Base):
     external_id = Column(String(100), nullable=True, index=True)  # 外部企业ID
     external_source = Column(String(50), nullable=True)  # 来源系统
     
+    # 国际化语言配置字段
+    default_language = Column(String(10), nullable=False, default='zh', server_default='zh', index=True)  # 租户默认语言
+    supported_languages = Column(ARRAY(String(10)), nullable=False, default=lambda: ['zh', 'en'], server_default=text("'{zh,en}'"))  # 租户支持的语言列表
+    
     # Relationship to users - one tenant has many users
     users = relationship("User", back_populates="tenant")
     

api/app/models/user_model.py

@@ -1,6 +1,6 @@
 import datetime
 import uuid
-from sqlalchemy import Column, String, Boolean, DateTime, ForeignKey
+from sqlalchemy import Column, String, Boolean, DateTime, ForeignKey, text
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
 from app.db import Base
@@ -22,6 +22,9 @@ class User(Base):
     external_id = Column(String(100), nullable=True)  # 外部用户ID
     external_source = Column(String(50), nullable=True)  # 来源系统
     
+    # 用户语言偏好
+    preferred_language = Column(String(10), server_default=text("'zh'"), default='zh', nullable=False, index=True)  # 用户偏好语言，默认中文
+    
     current_workspace_id = Column(UUID(as_uuid=True), ForeignKey("workspaces.id"), nullable=True)  # 当前工作空间ID，可为空
     
     # Foreign key to tenant - each user belongs to exactly one tenant

api/app/schemas/i18n_schema.py

@@ -0,0 +1,73 @@
+"""
+I18n Management API Schemas
+
+This module defines Pydantic schemas for i18n management APIs.
+"""
+
+from pydantic import BaseModel, Field
+from typing import Dict, List, Optional, Any
+
+
+# ============================================================================
+# Language Management Schemas
+# ============================================================================
+
+class LanguageInfo(BaseModel):
+    """Language information"""
+    code: str = Field(..., description="Language code (e.g., 'zh', 'en')")
+    name: str = Field(..., description="Language name (e.g., 'Chinese', 'English')")
+    native_name: str = Field(..., description="Native language name (e.g., '中文', 'English')")
+    is_enabled: bool = Field(..., description="Whether the language is enabled")
+    is_default: bool = Field(..., description="Whether this is the default language")
+
+
+class LanguageListResponse(BaseModel):
+    """Response for language list"""
+    languages: List[LanguageInfo] = Field(..., description="List of available languages")
+
+
+class LanguageCreateRequest(BaseModel):
+    """Request to add a new language"""
+    code: str = Field(..., description="Language code (e.g., 'ja', 'ko')", min_length=2, max_length=10)
+    name: str = Field(..., description="Language name", min_length=1, max_length=100)
+    native_name: str = Field(..., description="Native language name", min_length=1, max_length=100)
+    is_enabled: bool = Field(default=True, description="Whether to enable the language")
+
+
+class LanguageUpdateRequest(BaseModel):
+    """Request to update language configuration"""
+    is_enabled: Optional[bool] = Field(None, description="Whether the language is enabled")
+    is_default: Optional[bool] = Field(None, description="Whether this is the default language")
+
+
+# ============================================================================
+# Translation Management Schemas
+# ============================================================================
+
+class TranslationResponse(BaseModel):
+    """Response for translation data"""
+    translations: Dict[str, Dict[str, Any]] = Field(
+        ...,
+        description="Translations organized by locale and namespace"
+    )
+
+
+class TranslationUpdateRequest(BaseModel):
+    """Request to update a translation"""
+    value: str = Field(..., description="New translation value", min_length=1)
+    description: Optional[str] = Field(None, description="Optional description of the translation")
+
+
+class MissingTranslationsResponse(BaseModel):
+    """Response for missing translations"""
+    missing_translations: Dict[str, List[str]] = Field(
+        ...,
+        description="Missing translation keys organized by locale"
+    )
+
+
+class ReloadResponse(BaseModel):
+    """Response for translation reload"""
+    success: bool = Field(..., description="Whether the reload was successful")
+    reloaded_locales: List[str] = Field(..., description="List of reloaded locales")
+    total_locales: int = Field(..., description="Total number of available locales")

api/app/schemas/tenant_schema.py

@@ -11,6 +11,8 @@ class TenantBase(BaseModel):
     name: str = Field(..., description="租户名称", max_length=255)
     description: Optional[str] = Field(None, description="租户描述", max_length=1000)
     is_active: bool = Field(True, description="是否激活")
+    default_language: Optional[str] = Field('zh', description="租户默认语言", max_length=10)
+    supported_languages: Optional[List[str]] = Field(['zh', 'en'], description="租户支持的语言列表")
 
     @field_validator('name')
     @classmethod
@@ -18,6 +20,26 @@ class TenantBase(BaseModel):
         if not v or not v.strip():
             raise ValidationException('租户名称不能为空', code=BizCode.VALIDATION_FAILED)
         return v.strip()
+    
+    @field_validator('default_language')
+    @classmethod
+    def validate_default_language(cls, v):
+        if v:
+            # Validate language code format (2-letter code, optionally with region)
+            import re
+            if not re.match(r'^[a-z]{2}(-[A-Z]{2})?$', v):
+                raise ValidationException('语言代码格式不正确', code=BizCode.VALIDATION_FAILED)
+        return v
+    
+    @field_validator('supported_languages')
+    @classmethod
+    def validate_supported_languages(cls, v):
+        if v:
+            import re
+            for lang in v:
+                if not re.match(r'^[a-z]{2}(-[A-Z]{2})?$', lang):
+                    raise ValidationException(f'语言代码格式不正确: {lang}', code=BizCode.VALIDATION_FAILED)
+        return v
 
 
 class TenantCreate(TenantBase):
@@ -30,6 +52,8 @@ class TenantUpdate(BaseModel):
     name: Optional[str] = Field(None, description="租户名称", max_length=255)
     description: Optional[str] = Field(None, description="租户描述", max_length=1000)
     is_active: Optional[bool] = Field(None, description="是否激活")
+    default_language: Optional[str] = Field(None, description="租户默认语言", max_length=10)
+    supported_languages: Optional[List[str]] = Field(None, description="租户支持的语言列表")
 
     @field_validator('name')
     @classmethod
@@ -37,6 +61,25 @@ class TenantUpdate(BaseModel):
         if v is not None and (not v or not v.strip()):
             raise ValidationException('租户名称不能为空', code=BizCode.VALIDATION_FAILED)
         return v.strip() if v else v
+    
+    @field_validator('default_language')
+    @classmethod
+    def validate_default_language(cls, v):
+        if v:
+            import re
+            if not re.match(r'^[a-z]{2}(-[A-Z]{2})?$', v):
+                raise ValidationException('语言代码格式不正确', code=BizCode.VALIDATION_FAILED)
+        return v
+    
+    @field_validator('supported_languages')
+    @classmethod
+    def validate_supported_languages(cls, v):
+        if v:
+            import re
+            for lang in v:
+                if not re.match(r'^[a-z]{2}(-[A-Z]{2})?$', lang):
+                    raise ValidationException(f'语言代码格式不正确: {lang}', code=BizCode.VALIDATION_FAILED)
+        return v
 
 
 class Tenant(TenantBase):
@@ -62,4 +105,29 @@ class TenantList(BaseModel):
     total: int
     page: int
     size: int
-    pages: int
+    pages: int
+
+
+class TenantLanguageConfig(BaseModel):
+    """租户语言配置Schema"""
+    default_language: str = Field(..., description="租户默认语言", max_length=10)
+    supported_languages: List[str] = Field(..., description="租户支持的语言列表")
+    
+    @field_validator('default_language')
+    @classmethod
+    def validate_default_language(cls, v):
+        import re
+        if not re.match(r'^[a-z]{2}(-[A-Z]{2})?$', v):
+            raise ValidationException('语言代码格式不正确', code=BizCode.VALIDATION_FAILED)
+        return v
+    
+    @field_validator('supported_languages')
+    @classmethod
+    def validate_supported_languages(cls, v):
+        if not v:
+            raise ValidationException('支持的语言列表不能为空', code=BizCode.VALIDATION_FAILED)
+        import re
+        for lang in v:
+            if not re.match(r'^[a-z]{2}(-[A-Z]{2})?$', lang):
+                raise ValidationException(f'语言代码格式不正确: {lang}', code=BizCode.VALIDATION_FAILED)
+        return v

api/app/schemas/user_schema.py

@@ -58,6 +58,16 @@ class VerifyPasswordRequest(BaseModel):
     password: str = Field(..., description="密码")
 
 
+class LanguagePreferenceRequest(BaseModel):
+    """语言偏好设置请求"""
+    language: str = Field(..., min_length=2, max_length=10, description="语言代码，如 'zh', 'en'")
+
+
+class LanguagePreferenceResponse(BaseModel):
+    """语言偏好响应"""
+    language: str = Field(..., description="当前语言偏好")
+
+
 class ChangePasswordResponse(BaseModel):
     """修改密码响应"""
     message: str
@@ -74,6 +84,7 @@ class User(UserBase):
     current_workspace_id: Optional[uuid.UUID] = None
     current_workspace_name: Optional[str] = None
     role: Optional[WorkspaceRole] = None
+    preferred_language: Optional[str] = "zh"  # 用户语言偏好
 
     # 将 datetime 转换为毫秒时间戳
     @validator("created_at", pre=True)

api/app/services/auth_service.py

@@ -80,6 +80,7 @@ def authenticate_user_or_raise(db: Session, email: str, password: str) -> User:
     from app.core.exceptions import BusinessException
     from app.core.error_codes import BizCode
     from app.core.logging_config import get_auth_logger
+    from app.i18n.service import t
     
     logger = get_auth_logger()
     
@@ -87,17 +88,17 @@ def authenticate_user_or_raise(db: Session, email: str, password: str) -> User:
     user = user_repository.get_user_by_email(db, email=email)
     if not user:
         logger.warning(f"用户不存在: {email}")
-        raise BusinessException("用户不存在", code=BizCode.USER_NOT_FOUND)
+        raise BusinessException(t("auth.user.not_found"), code=BizCode.USER_NOT_FOUND)
     
     # 检查用户状态
     if not user.is_active:
         logger.warning(f"用户未激活: {email}")
-        raise BusinessException("用户未激活", code=BizCode.USER_NOT_FOUND)
+        raise BusinessException(t("auth.login.account_disabled"), code=BizCode.USER_NOT_FOUND)
     
     # 验证密码
     if not verify_password(password, user.hashed_password):
         logger.warning(f"密码错误: {email}")
-        raise BusinessException("密码错误", code=BizCode.PASSWORD_ERROR)
+        raise BusinessException(t("auth.password.incorrect"), code=BizCode.PASSWORD_ERROR)
     
     logger.info(f"用户认证成功: {email}")
     return user
@@ -254,6 +255,8 @@ def decode_access_token(token: str) -> dict:
     Raises:
         BusinessException: token 无效
     """
+    from app.i18n.service import t
+    
     try:
         payload = jwt.decode(token, TOKEN_SECRET_KEY, algorithms=[TOKEN_ALGORITHM])
         return {
@@ -261,4 +264,4 @@ def decode_access_token(token: str) -> dict:
             "share_token": payload["share_token"]
         }
     except jwt.InvalidTokenError:
-        raise BusinessException("无效的访问 token", BizCode.INVALID_TOKEN)
+        raise BusinessException(t("auth.token.invalid"), BizCode.INVALID_TOKEN)

api/app/services/tenant_service.py

@@ -217,4 +217,55 @@ class TenantService:
             skip=skip,
             limit=limit,
             is_active=is_active
-        )
+        )
+
+    def get_tenant_language_config(self, tenant_id: uuid.UUID) -> Optional[dict]:
+        """获取租户语言配置"""
+        tenant = self.tenant_repo.get_tenant_by_id(tenant_id)
+        if not tenant:
+            raise BusinessException("租户不存在", code=BizCode.TENANT_NOT_FOUND)
+        
+        return {
+            "default_language": tenant.default_language,
+            "supported_languages": tenant.supported_languages
+        }
+    
+    def update_tenant_language_config(
+        self, 
+        tenant_id: uuid.UUID, 
+        default_language: str,
+        supported_languages: list
+    ) -> Optional[dict]:
+        """更新租户语言配置"""
+        # 检查租户是否存在
+        tenant = self.tenant_repo.get_tenant_by_id(tenant_id)
+        if not tenant:
+            raise BusinessException("租户不存在", code=BizCode.TENANT_NOT_FOUND)
+        
+        # 验证默认语言在支持的语言列表中
+        if default_language not in supported_languages:
+            raise BusinessException(
+                "默认语言必须在支持的语言列表中",
+                code=BizCode.VALIDATION_FAILED
+            )
+        
+        try:
+            # 更新语言配置
+            tenant.default_language = default_language
+            tenant.supported_languages = supported_languages
+            self.db.commit()
+            self.db.refresh(tenant)
+            
+            business_logger.info(
+                f"更新租户语言配置成功: {tenant.name} (ID: {tenant.id}), "
+                f"默认语言: {default_language}, 支持语言: {supported_languages}"
+            )
+            
+            return {
+                "default_language": tenant.default_language,
+                "supported_languages": tenant.supported_languages
+            }
+        except Exception as e:
+            self.db.rollback()
+            business_logger.error(f"更新租户语言配置失败: {str(e)}")
+            raise BusinessException(f"更新租户语言配置失败: {str(e)}", code=BizCode.DB_ERROR)

api/app/services/user_service.py

@@ -438,24 +438,26 @@ def update_last_login_time(db: Session, user_id: uuid.UUID) -> User:
 
 async def change_password(db: Session, user_id: uuid.UUID, old_password: str, new_password: str, current_user: User) -> User:
     """普通用户修改自己的密码"""
+    from app.i18n.service import t
+    
     business_logger.info(f"用户修改密码请求: user_id={user_id}, current_user={current_user.id}")
     
     # 检查权限：只能修改自己的密码
     if current_user.id != user_id:
         business_logger.warning(f"用户尝试修改他人密码: current_user={current_user.id}, target_user={user_id}")
-        raise PermissionDeniedException("You can only change your own password")
+        raise PermissionDeniedException(t("auth.password.change_failed"))
     
     try:
         # 获取用户
         db_user = user_repository.get_user_by_id(db=db, user_id=user_id)
         if not db_user:
             business_logger.warning(f"用户不存在: {user_id}")
-            raise BusinessException("User not found", code=BizCode.USER_NOT_FOUND)
+            raise BusinessException(t("auth.user.not_found"), code=BizCode.USER_NOT_FOUND)
         
         # 验证旧密码
         if not verify_password(old_password, db_user.hashed_password):
             business_logger.warning(f"用户旧密码验证失败: {user_id}")
-            raise BusinessException("当前密码不正确", code=BizCode.VALIDATION_FAILED)
+            raise BusinessException(t("auth.password.incorrect"), code=BizCode.VALIDATION_FAILED)
         
         # 更新密码
         db_user.hashed_password = get_password_hash(new_password)
@@ -471,7 +473,7 @@ async def change_password(db: Session, user_id: uuid.UUID, old_password: str, ne
     except Exception as e:
         business_logger.error(f"修改用户密码失败: user_id={user_id} - {str(e)}")
         db.rollback()
-        raise BusinessException(f"修改用户密码失败: user_id={user_id} - {str(e)}", code=BizCode.DB_ERROR)
+        raise BusinessException(t("auth.password.change_failed"), code=BizCode.DB_ERROR)
 
 
 async def admin_change_password(db: Session, target_user_id: uuid.UUID, new_password: str = None, current_user: User = None) -> tuple[User, str]:
@@ -487,6 +489,8 @@ async def admin_change_password(db: Session, target_user_id: uuid.UUID, new_pass
     Returns:
         tuple[User, str]: (更新后的用户对象, 实际使用的密码)
     """
+    from app.i18n.service import t
+    
     business_logger.info(f"管理员修改用户密码请求: admin={current_user.id}, target_user={target_user_id}")
     
     # 检查权限：只有超级管理员可以修改他人密码
@@ -496,7 +500,7 @@ async def admin_change_password(db: Session, target_user_id: uuid.UUID, new_pass
     try:
         permission_service.check_superuser(
             subject,
-            error_message="只有超级管理员可以修改他人密码"
+            error_message=t("auth.password.change_failed")
         )
     except PermissionDeniedException as e:
         business_logger.warning(f"非超管用户尝试修改他人密码: current_user={current_user.id}")
@@ -507,12 +511,12 @@ async def admin_change_password(db: Session, target_user_id: uuid.UUID, new_pass
         target_user = user_repository.get_user_by_id(db=db, user_id=target_user_id)
         if not target_user:
             business_logger.warning(f"目标用户不存在: {target_user_id}")
-            raise BusinessException("目标用户不存在", code=BizCode.USER_NOT_FOUND)
+            raise BusinessException(t("auth.user.not_found"), code=BizCode.USER_NOT_FOUND)
         
         # 检查租户权限：超管只能修改同租户用户的密码
         if current_user.tenant_id != target_user.tenant_id:
             business_logger.warning(f"跨租户密码修改尝试: admin_tenant={current_user.tenant_id}, target_tenant={target_user.tenant_id}")
-            raise BusinessException("不可跨租户修改用户密码", code=BizCode.FORBIDDEN)
+            raise BusinessException(t("auth.password.change_failed"), code=BizCode.FORBIDDEN)
         
         # 如果没有提供新密码，则生成随机密码
         actual_password = new_password if new_password else generate_random_password()
@@ -532,7 +536,7 @@ async def admin_change_password(db: Session, target_user_id: uuid.UUID, new_pass
     except Exception as e:
         business_logger.error(f"管理员修改用户密码失败: admin={current_user.id}, target_user={target_user_id} - {str(e)}")
         db.rollback()
-        raise BusinessException(f"管理员修改用户密码失败: admin={current_user.id}, target_user={target_user_id} - {str(e)}", code=BizCode.DB_ERROR)
+        raise BusinessException(t("auth.password.change_failed"), code=BizCode.DB_ERROR)
 
 
 def generate_random_password(length: int = 12) -> str:
@@ -740,3 +744,54 @@ async def verify_and_change_email(db: Session, user_id: uuid.UUID, new_email: Em
 #
 #     business_logger.info(f"用户邮箱修改成功: {db_user.username}, new_email={new_email}")
 #     return db_user
+
+
+def get_user_language_preference(db: Session, user_id: uuid.UUID, current_user: User) -> str:
+    """获取用户语言偏好"""
+    business_logger.info(f"获取用户语言偏好: user_id={user_id}")
+    
+    # 权限检查：只能获取自己的语言偏好
+    if current_user.id != user_id:
+        raise PermissionDeniedException("只能获取自己的语言偏好")
+    
+    db_user = user_repository.get_user_by_id(db=db, user_id=user_id)
+    if not db_user:
+        raise BusinessException("用户不存在", code=BizCode.USER_NOT_FOUND)
+    
+    language = db_user.preferred_language or "zh"
+    business_logger.info(f"用户语言偏好: {db_user.username}, language={language}")
+    return language
+
+
+def update_user_language_preference(
+    db: Session, 
+    user_id: uuid.UUID, 
+    language: str, 
+    current_user: User
+) -> User:
+    """更新用户语言偏好"""
+    business_logger.info(f"更新用户语言偏好: user_id={user_id}, language={language}")
+    
+    # 权限检查：只能修改自己的语言偏好
+    if current_user.id != user_id:
+        raise PermissionDeniedException("只能修改自己的语言偏好")
+    
+    # 验证语言代码是否支持
+    from app.core.config import settings
+    if language not in settings.I18N_SUPPORTED_LANGUAGES:
+        raise BusinessException(
+            f"不支持的语言代码: {language}。支持的语言: {', '.join(settings.I18N_SUPPORTED_LANGUAGES)}",
+            code=BizCode.VALIDATION_FAILED
+        )
+    
+    db_user = user_repository.get_user_by_id(db=db, user_id=user_id)
+    if not db_user:
+        raise BusinessException("用户不存在", code=BizCode.USER_NOT_FOUND)
+    
+    # 更新语言偏好
+    db_user.preferred_language = language
+    db.commit()
+    db.refresh(db_user)
+    
+    business_logger.info(f"用户语言偏好更新成功: {db_user.username}, language={language}")
+    return db_user