feat: mobile-like window size and always-visible stats

- Changed window size to mobile phone format (400x800)
- Removed width condition for ActiveProxyFooter - now always visible
- Added run-umbrix.sh launch script with icon copying
- Stats cards now display on all screen sizes

lib/core/preferences/preferences_migration.dart

@@ -1,4 +1,4 @@
-import 'package:hiddify/utils/utils.dart';
+import 'package:umbrix/utils/utils.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 class PreferencesMigration with InfraLogger {