fix(ui): 게임 위젯들 레이아웃 및 스타일 수정

- death_overlay: 레이아웃 개선
- help_dialog, statistics_dialog: 스타일 통일
- notification_overlay: 간소화
- carousel_nav_bar: 스타일 업데이트
- mobile_carousel_layout: 레이아웃 조정

lib/src/features/game/layouts/mobile_carousel_layout.dart

@@ -355,11 +355,14 @@ class _MobileCarouselLayoutState extends State<MobileCarouselLayout> {
   /// 옵션 메뉴 표시
   void _showOptionsMenu(BuildContext context) {
     final localizations = L10n.of(context);
+    final panelBg = RetroColors.panelBgOf(context);
+    final gold = RetroColors.goldOf(context);
+    final surface = RetroColors.surfaceOf(context);
 
     showModalBottomSheet<void>(
       context: context,
       isScrollControlled: true,
-      backgroundColor: RetroColors.panelBg,
+      backgroundColor: panelBg,
       constraints: BoxConstraints(
         maxHeight: MediaQuery.of(context).size.height * 0.7,
       ),
@@ -372,18 +375,18 @@ class _MobileCarouselLayoutState extends State<MobileCarouselLayout> {
             Container(
               padding: const EdgeInsets.all(16),
               width: double.infinity,
-              decoration: const BoxDecoration(
-                color: RetroColors.darkBrown,
+              decoration: BoxDecoration(
+                color: surface,
                 border: Border(
-                  bottom: BorderSide(color: RetroColors.gold, width: 2),
+                  bottom: BorderSide(color: gold, width: 2),
                 ),
               ),
-              child: const Text(
+              child: Text(
                 'OPTIONS',
                 style: TextStyle(
                   fontFamily: 'PressStart2P',
                   fontSize: 12,
-                  color: RetroColors.gold,
+                  color: gold,
                 ),
               ),
             ),
@@ -558,23 +561,26 @@ class _MobileCarouselLayoutState extends State<MobileCarouselLayout> {
   @override
   Widget build(BuildContext context) {
     final state = widget.state;
+    final background = RetroColors.backgroundOf(context);
+    final panelBg = RetroColors.panelBgOf(context);
+    final gold = RetroColors.goldOf(context);
 
     return Scaffold(
-      backgroundColor: RetroColors.deepBrown,
+      backgroundColor: background,
       appBar: AppBar(
-        backgroundColor: RetroColors.darkBrown,
+        backgroundColor: panelBg,
         title: Text(
           L10n.of(context).progressQuestTitle(state.traits.name),
-          style: const TextStyle(
+          style: TextStyle(
             fontFamily: 'PressStart2P',
             fontSize: 10,
-            color: RetroColors.gold,
+            color: gold,
           ),
         ),
         actions: [
           // 옵션 버튼
           IconButton(
-            icon: const Icon(Icons.settings, color: RetroColors.gold),
+            icon: Icon(Icons.settings, color: gold),
             onPressed: () => _showOptionsMenu(context),
             tooltip: l10n.menuOptions,
           ),