Fix API compatibility and add user/role/permission and asset import/export

backend/app/db/__init__.py

@@ -0,0 +1,12 @@
+"""
+数据库模块初始化
+"""
+from app.db.session import engine, async_session_maker, get_db, init_db, close_db
+
+__all__ = [
+    "engine",
+    "async_session_maker",
+    "get_db",
+    "init_db",
+    "close_db",
+]