feat(remote): 修复键盘输入映射并重构连接流程

- Android端注入按键时显式设置SOURCE_KEYBOARD，修复IME丢弃事件导致输入框无法输入文字的问题
- Flutter端新增Flutter逻辑键到Android keyCode的转换映射，避免功能键误触发
- 重构RemoteController，分离信令连接与远程控制逻辑，支持设备列表选择与配对码兑换
- AuthRepository接口新增getBindings、getOnlineDevices、redeemPairingCode方法
- DioAuthRepository实现401自动刷新token重试机制
- ConnectionSessionState扩展设备列表、在线状态、配对码等状态字段

webrtc_controller_flutter/lib/l10n/app_localizations.dart

@@ -176,18 +176,6 @@ abstract class AppLocalizations {
   /// **'连接被控设备'**
   String get connectDevice;
 
-  /// No description provided for @serverUrl.
-  ///
-  /// In zh, this message translates to:
-  /// **'信令服务器地址:'**
-  String get serverUrl;
-
-  /// No description provided for @serverUrlPlaceholder.
-  ///
-  /// In zh, this message translates to:
-  /// **'wss://www.ttstd.com/signal'**
-  String get serverUrlPlaceholder;
-
   /// No description provided for @deviceId.
   ///
   /// In zh, this message translates to:
@@ -236,11 +224,11 @@ abstract class AppLocalizations {
   /// **'请输入用户名和密码'**
   String get usernamePasswordRequired;
 
-  /// No description provided for @serverAndTargetRequired.
+  /// No description provided for @targetRequired.
   ///
   /// In zh, this message translates to:
-  /// **'请填写服务器地址和目标设备ID'**
-  String get serverAndTargetRequired;
+  /// **'请填写目标设备ID'**
+  String get targetRequired;
 
   /// No description provided for @authTitle.
   ///
@@ -505,6 +493,72 @@ abstract class AppLocalizations {
   /// In zh, this message translates to:
   /// **'当前平台不支持自编码硬解。'**
   String get streamModeSelfCodecDesc;
+
+  /// No description provided for @boundDevices.
+  ///
+  /// In zh, this message translates to:
+  /// **'已绑定设备'**
+  String get boundDevices;
+
+  /// No description provided for @online.
+  ///
+  /// In zh, this message translates to:
+  /// **'在线'**
+  String get online;
+
+  /// No description provided for @offline.
+  ///
+  /// In zh, this message translates to:
+  /// **'离线'**
+  String get offline;
+
+  /// No description provided for @noBoundDevices.
+  ///
+  /// In zh, this message translates to:
+  /// **'暂无已绑定设备'**
+  String get noBoundDevices;
+
+  /// No description provided for @refreshDevices.
+  ///
+  /// In zh, this message translates to:
+  /// **'刷新'**
+  String get refreshDevices;
+
+  /// No description provided for @redeemPairingCode.
+  ///
+  /// In zh, this message translates to:
+  /// **'使用配对码绑定'**
+  String get redeemPairingCode;
+
+  /// No description provided for @pairingCodeHint.
+  ///
+  /// In zh, this message translates to:
+  /// **'请输入被控端显示的配对码'**
+  String get pairingCodeHint;
+
+  /// No description provided for @bindingFailed.
+  ///
+  /// In zh, this message translates to:
+  /// **'绑定失败：{error}'**
+  String bindingFailed(Object error);
+
+  /// No description provided for @deviceOfflineCannotConnect.
+  ///
+  /// In zh, this message translates to:
+  /// **'设备「{name}」当前不在线，无法连接'**
+  String deviceOfflineCannotConnect(Object name);
+
+  /// No description provided for @pleaseSelectDevice.
+  ///
+  /// In zh, this message translates to:
+  /// **'请先选择一个绑定的设备'**
+  String get pleaseSelectDevice;
+
+  /// No description provided for @bindSuccess.
+  ///
+  /// In zh, this message translates to:
+  /// **'绑定成功'**
+  String get bindSuccess;
 }
 
 class _AppLocalizationsDelegate