WIP: feat(ui): Migrate to new UI implementation

lib/features/preferences/data/repositories/local_preferences_repository.dart

@@ -2,12 +2,14 @@ import 'dart:convert';
 
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:injectable/injectable.dart';
+import 'package:moonwell_launcher/core/moonwell_theme_variant.dart';
 import 'package:moonwell_launcher/features/launcher/domain/entities/launcher_session.dart';
 import 'package:moonwell_launcher/features/preferences/domain/repositories/preferences_repository.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 const _outputDirKey = 'output_dir';
 const _launcherSessionKey = 'launcher_session';
+const _themeVariantKey = 'theme_variant';
 
 @LazySingleton(as: PreferencesRepository, env: ['flutter'])
 class LocalPreferencesRepository implements PreferencesRepository {
@@ -73,6 +75,18 @@ class LocalPreferencesRepository implements PreferencesRepository {
     await _maybeClearLegacyLauncherSession();
   }
 
+  @override
+  Future<MoonWellThemeVariant> getThemeVariant() async {
+    return MoonWellThemeVariant.fromStoredValue(
+      _preferences.getString(_themeVariantKey),
+    );
+  }
+
+  @override
+  Future<void> setThemeVariant(MoonWellThemeVariant variant) {
+    return _preferences.setString(_themeVariantKey, variant.name);
+  }
+
   Future<void> _maybeClearLegacyLauncherSession() async {
     if (_preferences.containsKey(_launcherSessionKey)) {
       await _preferences.remove(_launcherSessionKey);