feat(l10n): 게임 텍스트 다국어 지원 확장

- game_text_l10n.dart: 스탯/UI 텍스트 추가 (+61 라인)
- 한국어/일본어 번역 업데이트
- game_data_l10n.dart: 텍스트 접근자 추가
- equipment_stats_panel: l10n 적용 및 레이아웃 개선
- active_buff_panel, potion_inventory_panel: 코드 정리
- new_character_screen: 코드 정리
- progress_service: 마이너 개선

lib/src/features/game/game_play_screen.dart

@@ -174,6 +174,10 @@ class _GamePlayScreenState extends State<GamePlayScreen>
   /// 전투 이벤트를 메시지와 타입으로 변환
   (String, CombatLogType) _formatCombatEvent(CombatEvent event) {
     final target = event.targetName ?? '';
+    // 스킬/포션 이름 번역 (전역 로케일 사용)
+    final skillName = event.skillName != null
+        ? game_l10n.translateSpell(event.skillName!)
+        : '';
     return switch (event.type) {
       CombatEventType.playerAttack =>
         event.isCritical
@@ -208,41 +212,34 @@ class _GamePlayScreenState extends State<GamePlayScreen>
       CombatEventType.playerSkill =>
         event.isCritical
             ? (
-                game_l10n.combatSkillCritical(
-                  event.skillName ?? '',
-                  event.damage,
-                ),
+                game_l10n.combatSkillCritical(skillName, event.damage),
                 CombatLogType.critical,
               )
             : (
-                game_l10n.combatSkillDamage(event.skillName ?? '', event.damage),
+                game_l10n.combatSkillDamage(skillName, event.damage),
                 CombatLogType.spell,
               ),
       CombatEventType.playerHeal => (
         game_l10n.combatSkillHeal(
-          event.skillName ?? game_l10n.uiHeal,
+          skillName.isNotEmpty ? skillName : game_l10n.uiHeal,
           event.healAmount,
         ),
         CombatLogType.heal,
       ),
       CombatEventType.playerBuff => (
-        game_l10n.combatBuffActivated(event.skillName ?? ''),
+        game_l10n.combatBuffActivated(skillName),
         CombatLogType.buff,
       ),
       CombatEventType.dotTick => (
-        game_l10n.combatDotTick(event.skillName ?? '', event.damage),
+        game_l10n.combatDotTick(skillName, event.damage),
         CombatLogType.dotTick,
       ),
       CombatEventType.playerPotion => (
-        game_l10n.combatPotionUsed(
-          event.skillName ?? '',
-          event.healAmount,
-          target,
-        ),
+        game_l10n.combatPotionUsed(skillName, event.healAmount, target),
         CombatLogType.potion,
       ),
       CombatEventType.potionDrop => (
-        game_l10n.combatPotionDrop(event.skillName ?? ''),
+        game_l10n.combatPotionDrop(skillName),
         CombatLogType.potionDrop,
       ),
     };