feat(client): settings 完整版(开关组) + 联系/设置整页 golden

- settings_page 补全对照 dapp.jsx DSettings: 功能开关组(开机自启/智能分流/
  Kill Switch, 本地演示态) + 配置组补检查更新行; 改 ConsumerStatefulWidget 持开关态
- l10n 新增 autostart/smartRoute/killSwitch(+Sub) + checkUpdate(中英)
- desktop 整页 golden 补 联系页 + 设置页(凑齐可截 5 页: 节点/统计/账户/联系/设置)

测试: flutter test 81 通过(+2 golden), analyze 0 error

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/lib/l10n/app_text.dart

@@ -86,6 +86,13 @@ abstract class AppText {
   String get followLight;
   String get protocol;
   String get settingsTitle;
+  String get autostart;
+  String get autostartSub;
+  String get smartRoute;
+  String get smartRouteSub;
+  String get killSwitch;
+  String get killSwitchSub;
+  String get checkUpdate;
 
   // ── 套餐选择 ──
   String get choosePlan;