Handle websocket race condition

frontend/sync-client/src/services/websocket-manager.ts

@@ -188,6 +188,11 @@ export class WebSocketManager {
         this.webSocket = new this.webSocketFactoryImplementation(wsUri);
 
         this.webSocket.onopen = (): void => {
+            // Check if we've been stopped while connecting
+            if (this.isStopped) {
+                this.webSocket?.close(1000, "WebSocketManager was stopped during connection");
+                return;
+            }
             this.logger.info("WebSocket connection opened");
             this.onWebSocketStatusChanged.trigger(true);
         };