feat(front): 프론트 화면 개선 및 설정 저장소 추가

- front_screen_animation.dart: 프론트 화면 애니메이션 추가
- settings_repository.dart: 설정 저장소 구현
- front/widgets/: 프론트 화면 위젯 분리
- mobile_carousel_layout.dart: 모바일 레이아웃 개선
- app.dart: 앱 설정 개선
- game_text_l10n.dart: 텍스트 추가

lib/src/app.dart

@@ -10,6 +10,7 @@ import 'package:askiineverdie/src/core/model/pq_config.dart';
 import 'package:askiineverdie/src/core/notification/notification_service.dart';
 import 'package:askiineverdie/src/core/storage/save_manager.dart';
 import 'package:askiineverdie/src/core/storage/save_repository.dart';
+import 'package:askiineverdie/src/core/storage/settings_repository.dart';
 import 'package:askiineverdie/src/features/front/front_screen.dart';
 import 'package:askiineverdie/src/features/front/save_picker_dialog.dart';
 import 'package:askiineverdie/src/features/game/game_play_screen.dart';
@@ -28,8 +29,10 @@ class AskiiNeverDieApp extends StatefulWidget {
 class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
   late final GameSessionController _controller;
   late final NotificationService _notificationService;
+  late final SettingsRepository _settingsRepository;
   bool _isCheckingSave = true;
   bool _hasSave = false;
+  ThemeMode _themeMode = ThemeMode.system;
 
   @override
   void initState() {
@@ -47,11 +50,28 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
       saveManager: SaveManager(SaveRepository()),
     );
     _notificationService = NotificationService();
+    _settingsRepository = SettingsRepository();
 
+    // 초기 설정 로드
+    _loadSettings();
     // 세이브 파일 존재 여부 확인
     _checkForExistingSave();
   }
 
+  /// 저장된 설정 불러오기
+  Future<void> _loadSettings() async {
+    final themeMode = await _settingsRepository.loadThemeMode();
+    if (mounted) {
+      setState(() => _themeMode = themeMode);
+    }
+  }
+
+  /// 테마 모드 변경
+  void _changeThemeMode(ThemeMode mode) {
+    setState(() => _themeMode = mode);
+    _settingsRepository.saveThemeMode(mode);
+  }
+
   /// 세이브 파일 존재 여부 확인 후 자동 로드
   Future<void> _checkForExistingSave() async {
     final exists = await _controller.saveManager.saveExists();
@@ -70,6 +90,32 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
     super.dispose();
   }
 
+  /// 라이트 테마
+  ThemeData get _lightTheme => ThemeData(
+    colorScheme: ColorScheme.fromSeed(seedColor: const Color(0xFF234361)),
+    scaffoldBackgroundColor: const Color(0xFFF4F5F7),
+    useMaterial3: true,
+  );
+
+  /// 다크 테마 (OLED 저전력 모드 - 순수 검정)
+  ThemeData get _darkTheme => ThemeData(
+    colorScheme: ColorScheme.dark(
+      surface: Colors.black,
+      primary: const Color(0xFF4FC3F7), // 시안
+      secondary: const Color(0xFFFF4081), // 마젠타
+      onSurface: Colors.white70,
+      primaryContainer: const Color(0xFF1A3A4A),
+      onPrimaryContainer: Colors.white,
+    ),
+    scaffoldBackgroundColor: Colors.black,
+    useMaterial3: true,
+    // 카드/다이얼로그도 검정 배경 사용
+    cardColor: const Color(0xFF121212),
+    dialogTheme: const DialogThemeData(
+      backgroundColor: Color(0xFF121212),
+    ),
+  );
+
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
@@ -77,11 +123,9 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
       debugShowCheckedModeBanner: false,
       localizationsDelegates: L10n.localizationsDelegates,
       supportedLocales: L10n.supportedLocales,
-      theme: ThemeData(
-        colorScheme: ColorScheme.fromSeed(seedColor: const Color(0xFF234361)),
-        scaffoldBackgroundColor: const Color(0xFFF4F5F7),
-        useMaterial3: true,
-      ),
+      theme: _lightTheme,
+      darkTheme: _darkTheme,
+      themeMode: _themeMode,
       builder: (context, child) {
         // 현재 로케일을 게임 텍스트 l10n 시스템에 동기화
         final locale = Localizations.localeOf(context);
@@ -110,6 +154,8 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
           // 로드 실패 시 프론트 화면으로
           setState(() => _hasSave = false);
         },
+        currentThemeMode: _themeMode,
+        onThemeModeChange: _changeThemeMode,
       );
     }
 
@@ -118,6 +164,7 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
       onNewCharacter: _navigateToNewCharacter,
       onLoadSave: _loadSave,
       onHallOfFame: _navigateToHallOfFame,
+      hasSaveFile: _hasSave,
     );
   }
 
@@ -187,6 +234,8 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
           builder: (context) => GamePlayScreen(
             controller: _controller,
             forceCarouselLayout: testMode,
+            currentThemeMode: _themeMode,
+            onThemeModeChange: _changeThemeMode,
           ),
         ),
       );
@@ -196,7 +245,11 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
   void _navigateToGame(BuildContext context) {
     Navigator.of(context).push(
       MaterialPageRoute<void>(
-        builder: (context) => GamePlayScreen(controller: _controller),
+        builder: (context) => GamePlayScreen(
+          controller: _controller,
+          currentThemeMode: _themeMode,
+          onThemeModeChange: _changeThemeMode,
+        ),
       ),
     );
   }
@@ -235,10 +288,17 @@ class _SplashScreen extends StatelessWidget {
 
 /// 자동 로드 화면 (세이브 파일 자동 로드)
 class _AutoLoadScreen extends StatefulWidget {
-  const _AutoLoadScreen({required this.controller, required this.onLoadFailed});
+  const _AutoLoadScreen({
+    required this.controller,
+    required this.onLoadFailed,
+    required this.currentThemeMode,
+    required this.onThemeModeChange,
+  });
 
   final GameSessionController controller;
   final VoidCallback onLoadFailed;
+  final ThemeMode currentThemeMode;
+  final void Function(ThemeMode mode) onThemeModeChange;
 
   @override
   State<_AutoLoadScreen> createState() => _AutoLoadScreenState();
@@ -262,7 +322,8 @@ class _AutoLoadScreenState extends State<_AutoLoadScreen> {
         MaterialPageRoute<void>(
           builder: (context) => GamePlayScreen(
             controller: widget.controller,
-            // 자동 로드 시에는 플랫폼 기본값 사용 (모바일만 캐로셀)
+            currentThemeMode: widget.currentThemeMode,
+            onThemeModeChange: widget.onThemeModeChange,
           ),
         ),
       );
@@ -274,19 +335,19 @@ class _AutoLoadScreenState extends State<_AutoLoadScreen> {
 
   @override
   Widget build(BuildContext context) {
-    return const Scaffold(
+    return Scaffold(
       body: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
-            Text(
+            const Text(
               'ASCII NEVER DIE',
               style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
             ),
-            SizedBox(height: 16),
-            CircularProgressIndicator(),
-            SizedBox(height: 16),
-            Text('Loading...'),
+            const SizedBox(height: 16),
+            const CircularProgressIndicator(),
+            const SizedBox(height: 16),
+            Text(game_l10n.uiLoading),
           ],
         ),
       ),