feat: 重构 Web 端交互与 Mock 后端

app/src/db/session.py

@@ -0,0 +1,12 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+import os
+
+DATABASE_URL= os.getenv("DATABASE_URL")
+
+if not DATABASE_URL:
+    raise ValueError("DATABASE_URL environment variable is not set")
+
+engine = create_engine(
+    url=DATABASE_URL,
+)