修复健康监控

backend/main.py

@@ -25,6 +25,7 @@ from .routers.v1 import (
     auth_router, user_router, todos_router,
     notes_router, tools_router, stats_router
 )
+from sqlalchemy import text
 
 
 @asynccontextmanager
@@ -90,7 +91,8 @@ app.middleware("http")(log_requests)
 @app.get("/health")
 async def health_check(db: Session = Depends(get_db)):
     try:
-        db.execute("SELECT 1")
+        # 使用 text() 包裹 SQL 语句
+        db.execute(text("SELECT 1"))
         return {
             "status": "healthy",
             "database": "connected",