fix(realtime): eliminate cpu reconnect loop, singleton global connection & fix disappearing notes

frontend/src/features/lists/SharedListsView.tsx

@@ -105,7 +105,6 @@ export const SharedListsView: React.FC<SharedListsViewProps> = ({ onRefreshGloba
   const [dragOverItemTarget, setDragOverItemTarget] = useState<{ itemId: string; position: 'before' | 'after' } | null>(null);
   const [dragOverCategoryTarget, setDragOverCategoryTarget] = useState<string | null>(null);
 
-  const wsRef = useRef<WebSocket | null>(null);
   const realtimeConnRef = useRef<any>(null);
 
   const loadLists = async () => {