feat: add database session dependency for FastAPI routes

- Introduced a new dependency in `middleware/dependencies.py` to provide an asynchronous database session using SQLModel.
- This dependency can be utilized in route functions to facilitate database operations.

middleware/dependencies.py

@@ -0,0 +1,9 @@
+from typing import Annotated, AsyncGenerator
+
+from fastapi import Depends
+from sqlmodel.ext.asyncio.session import AsyncSession
+
+from models.database import get_session
+
+SessionDep = Annotated[AsyncSession, Depends(get_session)]
+"""数据库会话依赖，用于路由函数中获取数据库会话"""