feat(memory): add protected memory config deletion with end-user safeguards

- Add force parameter to delete_config endpoint for controlled deletion of in-use configs
- Implement MemoryConfigService.delete_config with protection against deleting default configs
- Add validation to prevent deletion of configs with connected end-users unless force=True
- Reorganize controller imports to remove duplicates and improve maintainability
- Clean up unused database connection management code from memory_storage_controller
- Add detailed docstring to delete_config endpoint explaining protection mechanisms
- Update error handling with specific BizCode.RESOURCE_IN_USE for configs in active use
- Add comprehensive logging for deletion attempts, warnings, and affected users
- Refactor ConfigParamsDelete schema usage to use MemoryConfigService directly
- Improve API response structure with affected_users count and force_required flag

api/app/models/end_user_model.py

@@ -1,11 +1,12 @@
 import datetime
 import uuid
 
-from app.db import Base
-from sqlalchemy import BigInteger, Column, DateTime, ForeignKey, Integer, String, Text
+from sqlalchemy import Column, DateTime, ForeignKey, String, Text
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
 
+from app.db import Base
+
 
 class EndUser(Base):
     __tablename__ = "end_users"
@@ -21,7 +22,13 @@ class EndUser(Base):
     updated_at = Column(DateTime, default=datetime.datetime.now, onupdate=datetime.datetime.now)
     
     # Memory config association - updated lazily during conversation
-    memory_config_id = Column(Integer, ForeignKey("data_config.config_id"), nullable=True, index=True, comment="关联的记忆配置ID")
+    memory_config_id = Column(
+        UUID(as_uuid=True), 
+        ForeignKey("memory_config.config_id"), 
+        nullable=True, 
+        index=True, 
+        comment="关联的记忆配置ID"
+    )
     
     # 用户基本信息字段
     position = Column(String, nullable=True, comment="职位")

api/app/models/memory_config_model.py

@@ -1,6 +1,8 @@
 import datetime
-from sqlalchemy import Column, String, Boolean, DateTime, Integer, Float
+
+from sqlalchemy import Boolean, Column, DateTime, Float, Integer, String
 from sqlalchemy.dialects.postgresql import UUID
+
 from app.db import Base
 
 
@@ -38,6 +40,7 @@ class MemoryConfig(Base):
 
     # 状态配置
     state = Column(Boolean, default=False, comment="配置使用状态")
+    is_default = Column(Boolean, default=False, comment="是否为工作空间默认配置")
 
     # 分块策略
     chunker_strategy = Column(String, default="RecursiveChunker", comment="分块策略")