feat(ui): 화면 및 공통 위젯 개선

- FrontScreen 개선
- GamePlayScreen, GameSessionController 업데이트
- ArenaBattleScreen, NewCharacterScreen 정리
- AsciiDisintegrateWidget 추가

lib/src/features/front/front_screen.dart

@@ -10,7 +10,7 @@ import 'package:asciineverdie/src/features/front/widgets/hero_vs_boss_animation.
 import 'package:asciineverdie/src/shared/retro_colors.dart';
 import 'package:asciineverdie/src/shared/widgets/retro_widgets.dart';
 
-class FrontScreen extends StatelessWidget {
+class FrontScreen extends StatefulWidget {
   const FrontScreen({
     super.key,
     this.onNewCharacter,
@@ -20,6 +20,8 @@ class FrontScreen extends StatelessWidget {
     this.hasSaveFile = false,
     this.savedGamePreview,
     this.hallOfFameCount = 0,
+    this.routeObserver,
+    this.onRefresh,
   });
 
   /// "New character" 버튼 클릭 시 호출
@@ -43,12 +45,45 @@ class FrontScreen extends StatelessWidget {
   /// 명예의 전당 캐릭터 수 (아레나 활성화 조건: 2명 이상)
   final int hallOfFameCount;
 
+  /// RouteObserver (화면 복귀 시 갱신용)
+  final RouteObserver<ModalRoute<void>>? routeObserver;
+
+  /// 화면 복귀 시 호출할 콜백
+  final VoidCallback? onRefresh;
+
+  @override
+  State<FrontScreen> createState() => _FrontScreenState();
+}
+
+class _FrontScreenState extends State<FrontScreen> with RouteAware {
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    // RouteObserver 구독
+    final route = ModalRoute.of(context);
+    if (route != null) {
+      widget.routeObserver?.subscribe(this, route);
+    }
+  }
+
+  @override
+  void dispose() {
+    widget.routeObserver?.unsubscribe(this);
+    super.dispose();
+  }
+
+  @override
+  void didPopNext() {
+    // 다른 화면에서 돌아왔을 때 갱신
+    widget.onRefresh?.call();
+  }
+
   /// 새 캐릭터 생성 시 세이브 파일 존재하면 경고 표시
   void _handleNewCharacter(BuildContext context) {
-    if (hasSaveFile) {
+    if (widget.hasSaveFile) {
       _showDeleteWarningDialog(context);
     } else {
-      onNewCharacter?.call(context);
+      widget.onNewCharacter?.call(context);
     }
   }
 
@@ -67,7 +102,7 @@ class FrontScreen extends StatelessWidget {
           FilledButton(
             onPressed: () {
               Navigator.pop(dialogContext);
-              onNewCharacter?.call(context);
+              widget.onNewCharacter?.call(context);
             },
             child: Text(game_l10n.buttonConfirm),
           ),
@@ -98,21 +133,21 @@ class FrontScreen extends StatelessWidget {
                         const _AnimationPanel(),
                         const SizedBox(height: 16),
                         _ActionButtons(
-                          onNewCharacter: onNewCharacter != null
+                          onNewCharacter: widget.onNewCharacter != null
                               ? () => _handleNewCharacter(context)
                               : null,
-                          onLoadSave: onLoadSave != null
-                              ? () => onLoadSave!(context)
+                          onLoadSave: widget.onLoadSave != null
+                              ? () => widget.onLoadSave!(context)
                               : null,
-                          onHallOfFame: onHallOfFame != null
-                              ? () => onHallOfFame!(context)
+                          onHallOfFame: widget.onHallOfFame != null
+                              ? () => widget.onHallOfFame!(context)
                               : null,
-                          onLocalArena:
-                              onLocalArena != null && hallOfFameCount >= 2
-                              ? () => onLocalArena!(context)
+                          onLocalArena: widget.onLocalArena != null &&
+                                  widget.hallOfFameCount >= 2
+                              ? () => widget.onLocalArena!(context)
                               : null,
-                          savedGamePreview: savedGamePreview,
-                          hallOfFameCount: hallOfFameCount,
+                          savedGamePreview: widget.savedGamePreview,
+                          hallOfFameCount: widget.hallOfFameCount,
                         ),
                       ],
                     ),
@@ -262,16 +297,14 @@ class _ActionButtons extends StatelessWidget {
               onPressed: onHallOfFame,
               isPrimary: false,
             ),
-          // 로컬 아레나 (2명 이상일 때만 활성화)
-          if (hallOfFameCount >= 2) ...[
-            const SizedBox(height: 12),
-            RetroTextButton(
-              text: game_l10n.uiLocalArena,
-              icon: Icons.sports_kabaddi,
-              onPressed: onLocalArena,
-              isPrimary: false,
-            ),
-          ],
+          // 로컬 아레나 (항상 표시, 2명 이상일 때만 활성화)
+          const SizedBox(height: 12),
+          RetroTextButton(
+            text: game_l10n.uiLocalArena,
+            icon: Icons.sports_kabaddi,
+            onPressed: hallOfFameCount >= 2 ? onLocalArena : null,
+            isPrimary: false,
+          ),
         ],
       ),
     );