feat(auth): 添加登录/注册页面及令牌恢复流程

- 新增 SplashPage（启动页）和 LoginPage（登录页），支持路由跳转
- 扩展 AuthState，增加 submitting/alert/busy 状态及消费机制
- AuthController 增加 checkLoginState/register/showAlert 等方法
- 删除旧模型文件（binding_item, token_response, verify_response）
- 删除旧版 LoginPage，迁移至 features/auth 目录
- 更新本地化字符串，增加注册相关文案
- 调整默认 API 地址为本地开发环境

webrtc_controller_flutter/lib/l10n/app_en.arb

@@ -3,6 +3,10 @@
   "appTitle": "WebRTC Controller",
   "login": "Login",
   "logout": "Logout",
+  "registerAccount": "Create Account",
+  "registerSuccess": "Registered successfully, please log in",
+  "registerFailed": "Registration failed: {error}",
+  "loginSubtitle": "Log in to connect your bound devices",
   "cancel": "Cancel",
   "confirm": "OK",
   "connect": "Connect",

webrtc_controller_flutter/lib/l10n/app_localizations.dart

@@ -116,6 +116,30 @@ abstract class AppLocalizations {
   /// **'退出登录'**
   String get logout;
 
+  /// No description provided for @registerAccount.
+  ///
+  /// In zh, this message translates to:
+  /// **'注册新账号'**
+  String get registerAccount;
+
+  /// No description provided for @registerSuccess.
+  ///
+  /// In zh, this message translates to:
+  /// **'注册成功，请登录'**
+  String get registerSuccess;
+
+  /// No description provided for @registerFailed.
+  ///
+  /// In zh, this message translates to:
+  /// **'注册失败：{error}'**
+  String registerFailed(Object error);
+
+  /// No description provided for @loginSubtitle.
+  ///
+  /// In zh, this message translates to:
+  /// **'登录后可连接已绑定的被控设备'**
+  String get loginSubtitle;
+
   /// No description provided for @cancel.
   ///
   /// In zh, this message translates to:

webrtc_controller_flutter/lib/l10n/app_localizations_en.dart

@@ -17,6 +17,20 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get logout => 'Logout';
 
+  @override
+  String get registerAccount => 'Create Account';
+
+  @override
+  String get registerSuccess => 'Registered successfully, please log in';
+
+  @override
+  String registerFailed(Object error) {
+    return 'Registration failed: $error';
+  }
+
+  @override
+  String get loginSubtitle => 'Log in to connect your bound devices';
+
   @override
   String get cancel => 'Cancel';
 

webrtc_controller_flutter/lib/l10n/app_localizations_zh.dart

@@ -17,6 +17,20 @@ class AppLocalizationsZh extends AppLocalizations {
   @override
   String get logout => '退出登录';
 
+  @override
+  String get registerAccount => '注册新账号';
+
+  @override
+  String get registerSuccess => '注册成功，请登录';
+
+  @override
+  String registerFailed(Object error) {
+    return '注册失败：$error';
+  }
+
+  @override
+  String get loginSubtitle => '登录后可连接已绑定的被控设备';
+
   @override
   String get cancel => '取消';
 

webrtc_controller_flutter/lib/l10n/app_zh.arb

@@ -3,6 +3,10 @@
   "appTitle": "WebRTC 控制端",
   "login": "登录",
   "logout": "退出登录",
+  "registerAccount": "注册新账号",
+  "registerSuccess": "注册成功，请登录",
+  "registerFailed": "注册失败：{error}",
+  "loginSubtitle": "登录后可连接已绑定的被控设备",
   "cancel": "取消",
   "confirm": "确定",
   "connect": "连接",