fix: 修复编译错误并添加WebSocket日志

- 修复MainActivity中语法错误导致的编译失败
- 在WebSocketClient中添加接收消息的调试日志

WebRTCControlled/app/src/main/java/com/ttstd/controlled/signaling/WebSocketClient.java

@@ -87,6 +87,7 @@ public class WebSocketClient {
 
             @Override
             public void onMessage(WebSocket webSocket, String text) {
+                Log.d(TAG, "WebSocket 收到消息: " + text);
                 SignalMessage msg = parse(text);
                 if (msg == null) return;
                 if ("REGISTER_SUCCESS".equals(msg.getType()) && msg.getFromDeviceId() != null) {