Replace flask_jwt_extended imports with quart_jwt

Fixes ModuleNotFoundError on server by using the custom
Quart-compatible JWT implementation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/utils.py

@@ -1,6 +1,6 @@
 from functools import wraps
 from flask import jsonify
-from flask_jwt_extended import get_jwt_identity
+from app.auth.quart_jwt import get_jwt_identity
 from app.models.user import User
 
 def admin_required(f):

backend/app/websocket_manager.py

@@ -14,7 +14,7 @@ from datetime import datetime
 from flask import request, current_app
 from flask_socketio import emit, join_room, leave_room, disconnect
 from .extensions import socketio_server as socketio  # Import singleton SocketIO instance
-from flask_jwt_extended import decode_token
+from app.auth.quart_jwt import decode_token
 from functools import wraps
 import json
 from queue import Queue

backend/app/websocket_manager_async.py

@@ -11,7 +11,7 @@ import asyncio
 from typing import Dict, Set, Any, Optional
 from datetime import datetime
 from .extensions import socketio_server as sio
-from flask_jwt_extended import decode_token
+from app.auth.quart_jwt import decode_token
 
 # Set up logging
 logger = logging.getLogger(__name__)