refactor(memory): extract workspace default config logic to service

- Extract default memory config retrieval logic from AppService to MemoryConfigService
- Make get_workspace_default_config method public (remove underscore prefix)
- Update AppService to delegate to MemoryConfigService for cleaner separation of concerns
- Add legacy int config_id handling in delete_config method with appropriate warnings
- Update delete_config signature to accept UUID or int types for backward compatibility
- Improve code reusability and maintainability by centralizing memory config operations

api/app/services/app_service.py

@@ -1316,43 +1316,18 @@ class AppService:
         Returns:
             Optional[uuid.UUID]: 默认记忆配置ID，如果不存在则返回 None
         """
-        from app.models.memory_config_model import MemoryConfig as MemoryConfigModel
+        from app.services.memory_config_service import MemoryConfigService
         
-        # 查找工作空间的默认记忆配置
-        stmt = (
-            select(MemoryConfigModel.id)
-            .where(
-                MemoryConfigModel.workspace_id == workspace_id,
-                MemoryConfigModel.is_default.is_(True),
-                MemoryConfigModel.state.is_(True),
-            )
-            .limit(1)
-        )
+        service = MemoryConfigService(self.db)
+        config = service.get_workspace_default_config(workspace_id)
         
-        config_id = self.db.scalars(stmt).first()
-        
-        if config_id:
-            return config_id
-        
-        # 回退：获取最早创建的活跃配置
-        stmt = (
-            select(MemoryConfigModel.id)
-            .where(
-                MemoryConfigModel.workspace_id == workspace_id,
-                MemoryConfigModel.state.is_(True),
-            )
-            .order_by(MemoryConfigModel.created_at.asc())
-            .limit(1)
-        )
-        
-        config_id = self.db.scalars(stmt).first()
-        
-        if not config_id:
+        if not config:
             logger.warning(
                 f"工作空间没有可用的记忆配置: workspace_id={workspace_id}"
             )
+            return None
         
-        return config_id
+        return config.id
 
     def _update_endusers_memory_config(
         self,

api/app/services/memory_config_service.py

@@ -445,7 +445,7 @@ class MemoryConfigService:
             "pruning_threshold": memory_config.pruning_threshold,
         }
 
-    def _get_workspace_default_config(
+    def get_workspace_default_config(
         self,
         workspace_id: UUID
     ) -> Optional["MemoryConfigModel"]:
@@ -529,7 +529,7 @@ class MemoryConfigService:
                 "End user has no memory config assigned",
                 extra={"end_user_id": str(end_user_id)}
             )
-            return self._get_workspace_default_config(workspace_id)
+            return self.get_workspace_default_config(workspace_id)
         
         config = self.db.get(MemoryConfigModel, end_user.memory_config_id)
         
@@ -545,7 +545,7 @@ class MemoryConfigService:
             }
         )
         
-        fallback_config = self._get_workspace_default_config(workspace_id)
+        fallback_config = self.get_workspace_default_config(workspace_id)
         
         if fallback_config:
             logger.info(
@@ -560,7 +560,7 @@ class MemoryConfigService:
 
     def delete_config(
         self,
-        config_id: UUID,
+        config_id: UUID | int,
         force: bool = False
     ) -> dict:
         """Delete memory config with protection against in-use configs.
@@ -569,7 +569,7 @@ class MemoryConfigService:
         that are actively being used by end users or marked as default.
         
         Args:
-            config_id: Memory config ID to delete
+            config_id: Memory config ID to delete (UUID or legacy int)
             force: If True, delete even if end users are connected
             
         Returns:
@@ -581,6 +581,18 @@ class MemoryConfigService:
         from app.core.exceptions import ResourceNotFoundException
         from app.models.memory_config_model import MemoryConfig as MemoryConfigModel
         
+        # 处理旧格式 int 类型的 config_id
+        if isinstance(config_id, int):
+            logger.warning(
+                "Attempted to delete legacy int config_id",
+                extra={"config_id": config_id}
+            )
+            return {
+                "status": "error",
+                "message": "旧格式配置ID不支持删除操作，请使用新版配置",
+                "legacy_int_id": config_id
+            }
+        
         config = self.db.get(MemoryConfigModel, config_id)
         if not config:
             raise ResourceNotFoundException("MemoryConfig", str(config_id))