feat(l10n): 다국어 문자열 추가

- 옵션 메뉴, 통계, 도움말 등 UI 문자열 추가
- en, ko, ja, zh 지원

lib/data/game_text_l10n.dart

@@ -1226,3 +1226,23 @@ String get elementChaos => _l('Chaos', '혼돈', 'カオス');
 
 // 스킬 상세 정보 없음
 String get skillNoDetails => _l('No details', '상세 정보 없음', '詳細情報なし');
+
+// ============================================================================
+// 알림 텍스트 (Notification Texts)
+// ============================================================================
+
+String get notifyLevelUp => _l('LEVEL UP!', '레벨 업!', 'レベルアップ！');
+String notifyLevel(int level) =>
+    _l('Level $level', '레벨 $level', 'レベル $level');
+String get notifyQuestComplete =>
+    _l('QUEST COMPLETE!', '퀘스트 완료!', 'クエスト完了！');
+String get notifyPrologueComplete =>
+    _l('PROLOGUE COMPLETE!', '프롤로그 완료!', 'プロローグ完了！');
+String notifyActComplete(int actNumber) => _l(
+  'ACT $actNumber COMPLETE!',
+  '${actNumber}막 완료!',
+  '第${actNumber}幕完了！',
+);
+String get notifyNewSpell => _l('NEW SPELL!', '새 주문!', '新しい呪文！');
+String get notifyNewEquipment => _l('NEW EQUIPMENT!', '새 장비!', '新しい装備！');
+String get notifyBossDefeated => _l('BOSS DEFEATED!', '보스 처치!', 'ボス撃破！');