Implement Alembic for database migrations and update FastAPI initialization

- Integrate Alembic for managing database schema migrations, replacing the previous SQL schema management.
- Update the FastAPI application to synchronize interface definitions at startup.
- Modify the Docker Compose command to run Alembic migrations before starting the API.
- Enhance the Makefile with new commands for database migration and revision management.
- Remove outdated SQL schema and seed files, transitioning to a more dynamic migration approach.
- Add initial migration scripts and configuration for Alembic, ensuring a structured database evolution.

backend/requirements.txt

@@ -18,5 +18,6 @@ websockets>=13
 
 # 存储:Postgres(SQLAlchemy 2.0 异步 + asyncpg 驱动)
 sqlalchemy[asyncio]>=2.0
+alembic>=1.13
 asyncpg
 greenlet  # SQLAlchemy 异步运行时必需(部分平台不会自动带上)