refactor: 重构 schemas 结构，统一枚举定义

backend/src/v1/memories/repository.py

@@ -9,7 +9,8 @@ from sqlalchemy.exc import SQLAlchemyError
 
 from core.db.base_repository import BaseRepository
 from core.logging import get_logger
-from models.memories import Memory, MemoryStatus, MemoryType
+from models.memories import Memory
+from schemas.enums import MemoryStatus, MemoryType
 
 if TYPE_CHECKING:
     from sqlalchemy.ext.asyncio import AsyncSession