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/features/connection/domain/binding_device.g.dart

@@ -0,0 +1,25 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'binding_device.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+BindingDevice _$BindingDeviceFromJson(Map<String, dynamic> json) =>
+    BindingDevice(
+      deviceUid: json['deviceUid'] as String? ?? '',
+      name: json['alias'] as String? ?? json['deviceUid'] as String? ?? '',
+      online: json['online'] as bool? ?? false,
+      authType: json['authType'] as String? ?? 'NONE',
+      lastSeen: json['lastSeen'] as int?,
+    );
+
+Map<String, dynamic> _$BindingDeviceToJson(BindingDevice instance) =>
+    <String, dynamic>{
+      'deviceUid': instance.deviceUid,
+      'alias': instance.name,
+      'online': instance.online,
+      'authType': instance.authType,
+      'lastSeen': instance.lastSeen,
+    };