feat(settings): sound & vibration toggle; themed settings screen

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/l10n/app_en.arb

@@ -59,5 +59,6 @@
   "removeAdsDescription": "Removes banners and full-screen ads. Reward ads stay available.",
   "restorePurchases": "Restore purchases",
   "adsRemovedThanks": "Ads removed — thank you!",
-  "purchaseUnavailable": "Purchases are unavailable right now."
+  "purchaseUnavailable": "Purchases are unavailable right now.",
+  "soundAndVibration": "Sound & vibration"
 }

lib/l10n/app_ko.arb

@@ -31,5 +31,6 @@
   "removeAdsDescription": "배너와 전면 광고를 제거합니다. 보상형 광고는 계속 사용할 수 있습니다.",
   "restorePurchases": "구매 복원",
   "adsRemovedThanks": "광고가 제거되었습니다 — 감사합니다!",
-  "purchaseUnavailable": "지금은 구매를 사용할 수 없습니다."
+  "purchaseUnavailable": "지금은 구매를 사용할 수 없습니다.",
+  "soundAndVibration": "소리 및 진동"
 }

lib/ui/screens/settings_screen.dart

@@ -2,8 +2,10 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
+import '../../game/models/season.dart';
 import '../../l10n/gen/app_localizations.dart';
 import '../../state/providers.dart';
+import '../widgets/season_background.dart';
 
 class SettingsScreen extends ConsumerWidget {
   const SettingsScreen({super.key});
@@ -12,6 +14,7 @@ class SettingsScreen extends ConsumerWidget {
   Widget build(BuildContext context, WidgetRef ref) {
     final l10n = AppLocalizations.of(context)!;
     final adsRemoved = ref.watch(adsRemovedProvider);
+    final soundOn = ref.watch(soundEnabledProvider);
     final iap = ref.read(iapServiceProvider);
 
     ref.listen<bool>(adsRemovedProvider, (prev, next) {
@@ -22,11 +25,26 @@ class SettingsScreen extends ConsumerWidget {
       }
     });
 
-    return Scaffold(
+    return Stack(
-      appBar: AppBar(title: Text(l10n.settings)),
+      fit: StackFit.expand,
+      children: [
+        const SeasonBackground(theme: SeasonTheme.fallback),
+        Scaffold(
+          backgroundColor: Colors.transparent,
+          appBar: AppBar(
+            backgroundColor: Colors.transparent,
+            title: Text(l10n.settings),
+          ),
           body: ListView(
             padding: const EdgeInsets.all(16),
             children: [
+              SwitchListTile(
+                title: Text(l10n.soundAndVibration),
+                value: soundOn,
+                onChanged: (v) =>
+                    ref.read(soundEnabledProvider.notifier).set(v),
+              ),
+              const Divider(),
               ListTile(
                 title: Text(l10n.removeAds),
                 subtitle: Text(l10n.removeAdsDescription),
@@ -53,6 +71,8 @@ class SettingsScreen extends ConsumerWidget {
               ),
             ],
           ),
+        ),
+      ],
     );
   }
 }