feat(end-user-api): add authenticated API endpoint for end user creation

- Should be merged  after v0.2.9
- Create new end_user_api_controller.py with POST /end_user/create endpoint
- Implement API Key authentication requirement with memory scope
- Add support for optional memory_config_id parameter with workspace default fallback
- Update memory_api_schema.py to remove workspace_id from request (now derived from API key auth)
- Add memory_config_id field to CreateEndUserResponse schema
- Register end_user_api_controller router in service module
- Migrate end user creation from unauthenticated to authenticated API flow

api/app/controllers/service/end_user_api_controller.py

@@ -0,0 +1,92 @@
+"""End User 服务接口 - 基于 API Key 认证"""
+
+import uuid
+
+from fastapi import APIRouter, Body, Depends, Request
+from sqlalchemy.orm import Session
+
+from app.core.api_key_auth import require_api_key
+from app.core.error_codes import BizCode
+from app.core.exceptions import BusinessException
+from app.core.logging_config import get_business_logger
+from app.core.response_utils import success
+from app.db import get_db
+from app.repositories.end_user_repository import EndUserRepository
+from app.schemas.api_key_schema import ApiKeyAuth
+from app.schemas.memory_api_schema import CreateEndUserRequest, CreateEndUserResponse
+from app.services.memory_config_service import MemoryConfigService
+
+router = APIRouter(prefix="/end_user", tags=["V1 - End User API"])
+logger = get_business_logger()
+
+
+@router.post("/create")
+@require_api_key(scopes=["memory"])
+async def create_end_user(
+    request: Request,
+    api_key_auth: ApiKeyAuth = None,
+    db: Session = Depends(get_db),
+    message: str = Body(..., description="Request body"),
+):
+    """
+    Create or retrieve an end user for the workspace.
+
+    Creates a new end user and connects it to a memory configuration.
+    If an end user with the same other_id already exists in the workspace,
+    returns the existing one.
+
+    Optionally accepts a memory_config_id to connect the end user to a specific
+    memory configuration. If not provided, falls back to the workspace default config.
+    """
+    body = await request.json()
+    payload = CreateEndUserRequest(**body)
+    workspace_id = api_key_auth.workspace_id
+
+    logger.info(f"Create end user request - other_id: {payload.other_id}, workspace_id: {workspace_id}")
+
+    # Resolve memory_config_id: explicit > workspace default
+    memory_config_id = None
+    config_service = MemoryConfigService(db)
+
+    if payload.memory_config_id:
+        try:
+            memory_config_id = uuid.UUID(payload.memory_config_id)
+        except ValueError:
+            raise BusinessException(
+                f"Invalid memory_config_id format: {payload.memory_config_id}",
+                BizCode.INVALID_PARAMETER
+            )
+        config = config_service.get_config_with_fallback(memory_config_id, workspace_id)
+        if not config:
+            raise BusinessException(
+                f"Memory config not found: {payload.memory_config_id}",
+                BizCode.MEMORY_CONFIG_NOT_FOUND
+            )
+        memory_config_id = config.config_id
+    else:
+        default_config = config_service.get_workspace_default_config(workspace_id)
+        if default_config:
+            memory_config_id = default_config.config_id
+            logger.info(f"Using workspace default memory config: {memory_config_id}")
+        else:
+            logger.warning(f"No default memory config found for workspace: {workspace_id}")
+
+    end_user_repo = EndUserRepository(db)
+    end_user = end_user_repo.get_or_create_end_user_with_config(
+        app_id=api_key_auth.resource_id,
+        workspace_id=workspace_id,
+        other_id=payload.other_id,
+        memory_config_id=memory_config_id,
+    )
+
+    logger.info(f"End user ready: {end_user.id}")
+
+    result = {
+        "id": str(end_user.id),
+        "other_id": end_user.other_id or "",
+        "other_name": end_user.other_name or "",
+        "workspace_id": str(end_user.workspace_id),
+        "memory_config_id": str(end_user.memory_config_id) if end_user.memory_config_id else None,
+    }
+
+    return success(data=CreateEndUserResponse(**result).model_dump(), msg="End user created successfully")