fix(client): 「我的」页加「设置」入口(我的设备下面)——iPad 竖屏/手机可达设置

iPad 竖屏回落 mobile 底 Tab(无侧栏),设置入口够不着。在账户页「我的设备」下面加一行
「设置」→ 下钻 SettingsScreen(复用桌面 SettingsPage + 移动返回栏)。与「联系我们」一致:
desktop/tablet 侧栏 + 账户页都可进。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/lib/screens/account_page.dart

@@ -63,6 +63,8 @@ class AccountPage extends ConsumerWidget {
         _Card(children: [
           _NavRow(icon: PangolinIcons.monitorSmartphone, title: t.myDevices, onTap: () => open(NavView.devices, DevicesScreen(t: t))),
           Divider(height: 1, color: c.border),
+          _NavRow(icon: PangolinIcons.settings, title: t.settingsTitle, onTap: () => open(NavView.settings, SettingsScreen(t: t))),
+          Divider(height: 1, color: c.border),
           _NavRow(icon: PangolinIcons.shoppingBag, title: t.redeemEntry, onTap: () => open(NavView.redeem, RedeemScreen(t: t))),
           Divider(height: 1, color: c.border),
           _NavRow(icon: PangolinIcons.messageCircle, title: t.contactEntry, onTap: () => open(NavView.contact, ContactScreen(t: t))),

client/lib/widgets/account_screens.dart

@@ -10,6 +10,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import '../l10n/app_text.dart';
 import '../models/device.dart';
 import '../pangolin_theme.dart';
+import '../screens/settings_page.dart';
 import '../services/device_identity.dart';
 import 'adaptive_menu.dart';
 import 'pangolin_field.dart';
@@ -52,6 +53,18 @@ class _SubScaffold extends StatelessWidget {
   }
 }
 
+/// ── 设置(移动端从「我的」下钻)── 复用桌面 SettingsPage 内容,套移动返回栏。
+class SettingsScreen extends StatelessWidget {
+  const SettingsScreen({super.key, required this.t, this.onBack});
+  final AppText t;
+  final VoidCallback? onBack;
+
+  @override
+  Widget build(BuildContext context) {
+    return _SubScaffold(title: t.settingsTitle, onBack: onBack, child: const SettingsPage());
+  }
+}
+
 /// ── 套餐选择 ── (价格/额度来自 GET /v1/plans;当前档由 me.plan 判定;
 /// 功能清单仍取 l10n,后端无此字段)
 class PlansScreen extends ConsumerWidget {