feat(client): 实时授权状态与会话失效处理

- 心跳读取 /auth/ping 回带的授权概况，直接刷新横幅/状态栏/只读门禁，省去单独轮询 /license/info
- 账号被停用/删除（401 USER_DISABLED）即强制重新登录
- 令牌持久化经串行队列 + 会话代号守卫，杜绝续期写入与登出交叉把失效 token 写回
- 写操作门禁（write_guard）+ 授权文案（license_copy）按 grace/readonly/locked 分阶段降级

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

client/lib/core/router/app_router.dart

@@ -142,7 +142,19 @@ final appRouterProvider = Provider<GoRouter>((ref) {
                   productId: int.parse(state.pathParameters['id']!)))),
           GoRoute(
               path: '/settings',
-              pageBuilder: (_, __) => _noTransition(const SettingsScreen())),
+              pageBuilder: (_, state) {
+                const tabIndex = {
+                  'shop': 0,
+                  'users': 1,
+                  'number': 2,
+                  'system': 3,
+                  'license': 4,
+                  'import': 5,
+                };
+                final tab =
+                    tabIndex[state.uri.queryParameters['tab']] ?? 0;
+                return _noTransition(SettingsScreen(initialTab: tab));
+              }),
           GoRoute(
               path: '/devices',
               pageBuilder: (_, __) =>