fix: resolve all compile errors from Stitch theme merge

- Add missing AppTheme animation constants (durationSm/Md/Lg/Xl, curveSmooth)
  to satisfy remote widget references.
- Replace deprecated GlassContainer(opacity:) with .glass()/.floating()/.base()
  in login_screen, live_tv_tab, mobile_live_tv_tab, player_screen,
  dashboard_screen.
- Fix const-eval errors by removing const from BorderSide/Text/BoxDecoration
  using AppColors.focusColor and AppColors.border (runtime getters).
- Fix subtitle_service.dart: padEnd → padRight (Dart String API).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/features/admin/screens/admin_panel.dart

@@ -558,7 +558,7 @@ class _UsersTab extends ConsumerWidget {
                                             .withOpacity(0.2),
                                         borderRadius: BorderRadius.circular(50),
                                       ),
-                                      child: const Text(
+                                      child: Text(
                                         'ADMIN',
                                         style: TextStyle(
                                           fontSize: 10,