fix(client): start LAN carrier polling (led.lan was never started)

lib/client.js

@@ -91,6 +91,9 @@ class ClawClient {
 
     this._startSdNotify();
 
+    // RJ45 链路轮询（OpenVFD play），与 WS 无关，进程起来即开始
+    led.lan.start();
+
     // 启动蓝牙状态监控（独立于网络，立即开始）
     this._btMonitor = new BtMonitor();
     this._btMonitor.start();