update : gameover

lib/screens/battle_screen.dart

@@ -13,6 +13,7 @@ import '../widgets/battle/character_status_card.dart';
 import '../widgets/battle/battle_log_overlay.dart';
 import '../widgets/battle/floating_battle_texts.dart';
 import '../widgets/battle/stage_ui.dart';
+import 'main_menu_screen.dart';
 
 class BattleScreen extends StatefulWidget {
   const BattleScreen({super.key});
@@ -527,6 +528,50 @@ class _BattleScreenState extends State<BattleScreen> {
               ..._floatingDamageTexts.map((e) => e.widget),
               ..._floatingEffects.map((e) => e.widget),
               ..._floatingFeedbackTexts.map((e) => e.widget),
+
+              // Game Over Overlay
+              if (battleProvider.player.isDead)
+                Container(
+                  color: Colors.black87,
+                  child: Center(
+                    child: Column(
+                      mainAxisSize: MainAxisSize.min,
+                      children: [
+                        const Text(
+                          "DEFEAT",
+                          style: TextStyle(
+                            color: Colors.red,
+                            fontSize: 48,
+                            fontWeight: FontWeight.bold,
+                            letterSpacing: 4.0,
+                          ),
+                        ),
+                        const SizedBox(height: 32),
+                        ElevatedButton(
+                          style: ElevatedButton.styleFrom(
+                            backgroundColor: Colors.grey[800],
+                            padding: const EdgeInsets.symmetric(
+                              horizontal: 32,
+                              vertical: 16,
+                            ),
+                          ),
+                          onPressed: () {
+                            Navigator.of(context).pushAndRemoveUntil(
+                              MaterialPageRoute(
+                                builder: (context) => const MainMenuScreen(),
+                              ),
+                              (route) => false,
+                            );
+                          },
+                          child: const Text(
+                            "Return to Main Menu",
+                            style: TextStyle(color: Colors.white, fontSize: 18),
+                          ),
+                        ),
+                      ],
+                    ),
+                  ),
+                ),
             ],
           );
         },