feat: 增加信令自动重连保活与控制端视频录制

- 信令客户端增加心跳保活与指数退避自动重连机制
- 服务端优化传输异常日志级别，客户端断开不再报错
- 被控端信令断开时保持服务运行并自动重连
- Flutter 控制端增加远程视频录制功能，兼容标准 WebRTC 模式切换
- 各端连接按钮增加“连接中”状态防重复点击

webrtc_controller_flutter/lib/main.dart

@@ -9,6 +9,7 @@ import 'controller/remote_controller.dart';
 import 'utils/control_commands.dart';
 import 'utils/device_utils.dart';
 import 'webrtc/self_codec_decoder.dart';
+import 'webrtc/video_recorder.dart';
 import 'widgets/remote_touch_view.dart';
 
 void main() {
@@ -52,6 +53,8 @@ class _ControllerHomeState extends State<ControllerHome> {
   RTCVideoRenderer? _renderer;
 
   bool _connected = false;
+  /// 是否正在连接信令服务器 / 建立 WebRTC（连接过程中禁用“连接”按钮）。
+  bool _connecting = false;
   String _status = '状态: 已停止';
   String _stats = '';
   double _videoAspect = 16 / 9;
@@ -62,6 +65,13 @@ class _ControllerHomeState extends State<ControllerHome> {
   bool _selfCodecReady = false;
   bool _selfCodecSupported = true;
 
+  /// 远程视频录制器（基于 flutter_webrtc 的 MediaRecorder）。
+  final VideoRecorder _videoRecorder = VideoRecorder();
+  bool _recording = false;
+  String _recordStatus = '';
+  /// 自编码模式下请求录制时，先切回 WebRTC 标准模式、待就绪后再开始录制。
+  bool _pendingRecordStart = false;
+
   /// 分辨率预设：width 为长边像素；0 表示被控端原生分辨率；
   /// height 传 0（由被控端按屏幕宽高比计算），fps 传 0（沿用当前帧率）。
   int _selectedResolution = 0;
@@ -88,6 +98,7 @@ class _ControllerHomeState extends State<ControllerHome> {
 
   @override
   void dispose() {
+    _videoRecorder.dispose();
     _controller?.disconnect();
     _serverUrlController.dispose();
     _deviceIdController.dispose();
@@ -266,6 +277,7 @@ class _ControllerHomeState extends State<ControllerHome> {
       return;
     }
 
+    setState(() => _connecting = true);
     _setStatus('状态: 正在连接信令服务器...');
 
     _controller = RemoteController(
@@ -279,11 +291,19 @@ class _ControllerHomeState extends State<ControllerHome> {
     _controller!.onConnectionEstablished = () {
       setState(() {
         _connected = true;
+        _connecting = false;
         _status = '状态: 已连接 - 远程控制中';
       });
     };
+    _controller!.onConnectionFailed = (error) {
+      if (mounted) setState(() => _connecting = false);
+      _showAlert('连接失败：$error');
+    };
     _controller!.onDisconnected = () {
-      setState(() => _connected = false);
+      setState(() {
+        _connected = false;
+        _connecting = false;
+      });
       _setStatus('状态: 远端已断开');
     };
     _controller!.onIceDisconnected = (message) {
@@ -298,6 +318,10 @@ class _ControllerHomeState extends State<ControllerHome> {
     _controller!.onRemoteStream = (renderer) {
       setState(() => _renderer = renderer);
       renderer.addListener(_onRendererUpdate);
+      if (_pendingRecordStart) {
+        _pendingRecordStart = false;
+        _startRecording();
+      }
     };
     _controller!.onStats = (stats) => setState(() => _stats = stats);
     _controller!.onSelfCodecReady = (textureId) {
@@ -318,6 +342,10 @@ class _ControllerHomeState extends State<ControllerHome> {
     };
     _controller!.onStreamModeReport = (mode) {
       if (mounted) setState(() => _streamMode = mode);
+      if (mode == SelfCodecDecoder.streamModeWebRtc && _pendingRecordStart) {
+        _pendingRecordStart = false;
+        _startRecording();
+      }
     };
     _controller!.onResolutionReported = (w, h) {
       if (w > 0 && h > 0 && mounted) {
@@ -363,13 +391,19 @@ class _ControllerHomeState extends State<ControllerHome> {
   /// 目标被控端不在线：提示用户并复位到连接设置面板。
   Future<void> _onTargetOffline(String message) async {
     _showAlert(message);
-    setState(() => _connected = false);
+    setState(() {
+      _connected = false;
+      _connecting = false;
+    });
   }
 
   /// 被控端拒绝连接请求：提示用户并复位到连接设置面板。
   Future<void> _onConnectionRejected(String message) async {
     _showAlert(message);
-    setState(() => _connected = false);
+    setState(() {
+      _connected = false;
+      _connecting = false;
+    });
   }
 
   /// 弹出分辨率选择菜单（iOS 风格 ActionSheet）。
@@ -426,13 +460,70 @@ class _ControllerHomeState extends State<ControllerHome> {
     _controller?.sendStreamMode(next);
   }
 
+  /// 切换远程视频录制：开始 / 停止。
+  Future<void> _toggleRecord() async {
+    if (_recording) {
+      await _stopRecording();
+      return;
+    }
+    if (_renderer == null) {
+      _showAlert('尚未连接或没有视频画面，无法录制');
+      return;
+    }
+    if (_streamMode == SelfCodecDecoder.streamModeSelfCodec) {
+      // 自编码模式下没有 WebRTC 视频轨道，先切回标准模式再开始录制。
+      _pendingRecordStart = true;
+      setState(() => _recordStatus = '正在切回标准模式以开始录制...');
+      _controller?.sendStreamMode(SelfCodecDecoder.streamModeWebRtc);
+      return;
+    }
+    await _startRecording();
+  }
+
+  /// 开始录制当前远端视频轨道。
+  Future<void> _startRecording() async {
+    if (_recording || !mounted) return;
+    final stream = _renderer?.srcObject;
+    if (stream == null) {
+      _showAlert('尚未接收到视频画面，无法录制');
+      return;
+    }
+    try {
+      final ok = await _videoRecorder.start(stream);
+      if (ok && mounted) {
+        setState(() {
+          _recording = true;
+          _recordStatus = '录制中...';
+        });
+      }
+    } catch (e) {
+      if (mounted) {
+        setState(() => _recordStatus = '');
+        _showAlert('开始录制失败：$e');
+      }
+    }
+  }
+
+  /// 停止录制并提示保存位置。
+  Future<void> _stopRecording() async {
+    final path = await _videoRecorder.stop();
+    if (mounted) {
+      setState(() {
+        _recording = false;
+        _recordStatus = path != null ? '已保存：$path' : '录制已停止';
+      });
+    }
+  }
+
   Future<void> _disconnect() async {
+    await _videoRecorder.dispose();
     await _controller?.disconnect();
     _controller = null;
     _renderer?.removeListener(_onRendererUpdate);
     _lastResizedAspect = 0;
     setState(() {
       _connected = false;
+      _connecting = false;
       _renderer = null;
       _status = '状态: 已停止';
       _stats = '';
@@ -440,6 +531,9 @@ class _ControllerHomeState extends State<ControllerHome> {
       _selfCodecTextureId = null;
       _selfCodecReady = false;
       _selfCodecSupported = true;
+      _recording = false;
+      _recordStatus = '';
+      _pendingRecordStart = false;
     });
   }
 
@@ -501,8 +595,8 @@ class _ControllerHomeState extends State<ControllerHome> {
             SizedBox(
               width: double.infinity,
               child: CupertinoButton.filled(
-                onPressed: _showAuthDialog,
-                child: const Text('连接被控设备'),
+                onPressed: _connecting ? null : _showAuthDialog,
+                child: Text(_connecting ? '正在连接...' : '连接被控设备'),
               ),
             ),
           ],
@@ -569,6 +663,33 @@ class _ControllerHomeState extends State<ControllerHome> {
               ],
             ),
           ),
+          // 远程视频录制开关
+          CupertinoButton(
+            padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
+            onPressed: _toggleRecord,
+            child: Row(
+              mainAxisSize: MainAxisSize.min,
+              children: [
+                Icon(
+                  _recording
+                      ? CupertinoIcons.stop_circle
+                      : CupertinoIcons.video_camera,
+                  color: _recording
+                      ? CupertinoColors.destructiveRed
+                      : CupertinoColors.white,
+                  size: 20,
+                ),
+                const SizedBox(width: 6),
+                Text(
+                  _recording ? '停止' : '录制',
+                  style: const TextStyle(
+                    color: CupertinoColors.white,
+                    fontSize: 14,
+                  ),
+                ),
+              ],
+            ),
+          ),
           // 分隔线
           Container(
             width: 1,
@@ -668,6 +789,14 @@ class _ControllerHomeState extends State<ControllerHome> {
                   _stats,
                   style: const TextStyle(color: Colors.white, fontSize: 12),
                 ),
+                if (_recordStatus.isNotEmpty)
+                  Text(
+                    _recordStatus,
+                    style: const TextStyle(
+                      color: CupertinoColors.systemOrange,
+                      fontSize: 12,
+                    ),
+                  ),
               ],
             ),
           ),