feat(i18n): 다국어 번역 확장 및 UI 개선

- 영어/일본어/한국어/중국어 번역 추가
- VictoryOverlay 레이아웃 개선
- NewCharacterScreen 기능 추가

lib/l10n/app_localizations.dart

@@ -544,6 +544,102 @@ abstract class L10n {
   /// In en, this message translates to:
   /// **'Sold!'**
   String get soldButton;
+
+  /// Victory overlay congratulations
+  ///
+  /// In en, this message translates to:
+  /// **'★ CONGRATULATIONS ★'**
+  String get endingCongratulations;
+
+  /// Game completion message
+  ///
+  /// In en, this message translates to:
+  /// **'You have completed the game!'**
+  String get endingGameComplete;
+
+  /// Hero section title
+  ///
+  /// In en, this message translates to:
+  /// **'THE HERO'**
+  String get endingTheHero;
+
+  /// Level display format
+  ///
+  /// In en, this message translates to:
+  /// **'Level {level}'**
+  String endingLevelFormat(int level);
+
+  /// Journey statistics section title
+  ///
+  /// In en, this message translates to:
+  /// **'JOURNEY STATISTICS'**
+  String get endingJourneyStats;
+
+  /// Monsters killed stat label
+  ///
+  /// In en, this message translates to:
+  /// **'Monsters Slain'**
+  String get endingMonstersSlain;
+
+  /// Quests completed stat label
+  ///
+  /// In en, this message translates to:
+  /// **'Quests Completed'**
+  String get endingQuestsCompleted;
+
+  /// Play time stat label
+  ///
+  /// In en, this message translates to:
+  /// **'Play Time'**
+  String get endingPlayTime;
+
+  /// Final stats section title
+  ///
+  /// In en, this message translates to:
+  /// **'FINAL STATS'**
+  String get endingFinalStats;
+
+  /// Credits section title
+  ///
+  /// In en, this message translates to:
+  /// **'CREDITS'**
+  String get endingCredits;
+
+  /// Thank you message
+  ///
+  /// In en, this message translates to:
+  /// **'Thank you for playing!'**
+  String get endingThankYou;
+
+  /// Legend message
+  ///
+  /// In en, this message translates to:
+  /// **'Your legend lives on...'**
+  String get endingLegendLivesOn;
+
+  /// Hall of fame message line 1
+  ///
+  /// In en, this message translates to:
+  /// **'Your heroic deeds will be'**
+  String get endingHallOfFameLine1;
+
+  /// Hall of fame message line 2
+  ///
+  /// In en, this message translates to:
+  /// **'remembered in the Hall of Fame'**
+  String get endingHallOfFameLine2;
+
+  /// Skip button
+  ///
+  /// In en, this message translates to:
+  /// **'SKIP'**
+  String get endingSkip;
+
+  /// Tap to skip hint
+  ///
+  /// In en, this message translates to:
+  /// **'TAP TO SKIP'**
+  String get endingTapToSkip;
 }
 
 class _L10nDelegate extends LocalizationsDelegate<L10n> {