Fix import path: use database not app.database

backend/main.py

@@ -993,7 +993,7 @@ async def export_html_report(
     from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
     from jose import JWTError, jwt
     from database import SECRET_KEY, ALGORITHM
-    from app.database import get_db
+    from database import get_db
     
     credentials_exception = HTTPException(
         status_code=401,