Code reviewed and issue fixed.

app/__init__.py

@@ -112,7 +112,10 @@ def create_app(config_name=None):
 
     @login_manager.user_loader
     def load_user(user_id):
-        return User.query.get(int(user_id))
+        # db.session.get() is the SQLAlchemy 2.x successor to the deprecated
+        # Model.query.get(). Both hit the identity map first (no SQL if the
+        # object is already in session), then fall back to a SELECT by PK.
+        return db.session.get(User, int(user_id))
 
     # ── Context processors ────────────────────────────────────────────────────
     @app.context_processor