feat(core): i18n 및 핵심 로직 개선

- 수익화 관련 텍스트 추가
- item_service 수정
- progress_service 수정

lib/data/game_text_l10n.dart

@@ -141,14 +141,56 @@ String get deathNoSacrificeNeeded =>
     _l('No sacrifice needed', '희생 없이 부활', '犠牲なしで復活');
 String get deathCoinRemaining => _l('Coin Remaining', '남은 코인', '残りコイン');
 String get deathResurrect => _l('Resurrect', '부활', '復活');
-String get deathAutoResurrect => _l('Auto Resurrect', '자동 부활', '自動復活');
 String get deathCombatLog => _l('Combat Log', '전투 기록', '戦闘ログ');
 
+// 광고 부활 (통합)
+String get deathAdRevive => _l('Watch Ad & Revive', '광고보고 부활', '広告視聴で復活');
+String get deathAdReviveHp => _l('HP 100% Recovery', 'HP 100% 회복', 'HP 100%回復');
+String get deathAdReviveItem => _l('Item Recovery', '아이템 복구', 'アイテム回収');
+String get deathAdReviveAuto =>
+    _l('10min Auto-Revive Buff', '10분간 자동부활 버프', '10分間自動復活バフ');
+String get deathAdRevivePaidDesc =>
+    _l('Premium: No ads required', '프리미엄: 광고 없이 이용', 'プレミアム: 広告不要');
+
 String deathKilledBy(String killerName) =>
     _l('Killed by $killerName', '$killerName에게 사망', '$killerNameに倒された');
 String get deathEnvironmentalHazard =>
     _l('Environmental hazard', '환경 피해로 사망', '環境ダメージで死亡');
 
+// ============================================================================
+// 속도 부스트 (Phase 6)
+// ============================================================================
+
+String get speedBoostTitle =>
+    _l('Speed Boost', '속도 부스트', 'スピードブースト');
+String get speedBoostActivate =>
+    _l('Activate 10x Speed', '10배속 활성화', '10倍速を有効化');
+String speedBoostRemaining(int seconds) =>
+    _l('${seconds}s remaining', '${seconds}초 남음', '残り${seconds}秒');
+String get speedBoostActive =>
+    _l('BOOST ACTIVE', '부스트 활성화', 'ブースト中');
+
+// ============================================================================
+// 복귀 보상 (Phase 7)
+// ============================================================================
+
+String get returnRewardTitle =>
+    _l('Welcome Back!', '돌아오셨군요!', 'おかえりなさい!');
+String returnRewardHoursAway(String time) =>
+    _l('You were away for $time', '$time 동안 떠나있었습니다', '$time 離れていました');
+String get returnRewardBasic =>
+    _l('Basic Reward', '기본 보상', '基本報酬');
+String get returnRewardBonus =>
+    _l('Bonus Reward', '보너스 보상', 'ボーナス報酬');
+String returnRewardGold(int gold) =>
+    _l('+$gold Gold', '+$gold 골드', '+$gold ゴールド');
+String get returnRewardClaim =>
+    _l('Claim', '받기', '受け取る');
+String get returnRewardClaimBonus =>
+    _l('Claim Bonus', '보너스 받기', 'ボーナス受取');
+String get returnRewardSkip =>
+    _l('Skip', '건너뛰기', 'スキップ');
+
 // ============================================================================
 // UI 일반 메시지
 // ============================================================================

lib/src/core/engine/item_service.dart

@@ -60,23 +60,26 @@ class ItemService {
   // 희귀도 결정
   // ============================================================================
 
-  /// 희귀도 결정 (레벨 기반 확률)
+  /// 희귀도 결정 (고정 확률)
   ///
-  /// 레벨이 높을수록 희귀한 아이템 확률 증가
+  /// 확률 분포:
+  /// - Common: 34%
+  /// - Uncommon: 40%
+  /// - Rare: 20%
+  /// - Epic: 5%
+  /// - Legendary: 1%
   ItemRarity determineRarity(int level) {
     final roll = rng.nextInt(100);
-    final legendaryChance = (level * 0.5).clamp(0, 5).toInt(); // 최대 5%
-    final epicChance = (level * 1.0).clamp(0, 10).toInt(); // 최대 10%
-    final rareChance = (level * 2.0).clamp(0, 20).toInt(); // 최대 20%
-    final uncommonChance = (level * 3.0).clamp(0, 30).toInt(); // 최대 30%
 
-    if (roll < legendaryChance) return ItemRarity.legendary;
+    // Legendary: 0-0 (1%)
-    if (roll < legendaryChance + epicChance) return ItemRarity.epic;
+    if (roll < 1) return ItemRarity.legendary;
-    if (roll < legendaryChance + epicChance + rareChance)
+    // Epic: 1-5 (5%)
-      return ItemRarity.rare;
+    if (roll < 6) return ItemRarity.epic;
-    if (roll < legendaryChance + epicChance + rareChance + uncommonChance) {
+    // Rare: 6-25 (20%)
-      return ItemRarity.uncommon;
+    if (roll < 26) return ItemRarity.rare;
-    }
+    // Uncommon: 26-65 (40%)
+    if (roll < 66) return ItemRarity.uncommon;
+    // Common: 66-99 (34%)
     return ItemRarity.common;
   }
 

lib/src/core/engine/progress_service.dart

@@ -972,12 +972,16 @@ class ProgressService {
     String? lostItemName;
     EquipmentSlot? lostItemSlot;
     ItemRarity? lostItemRarity;
+    EquipmentItem? lostEquipmentItem; // 광고 부활 시 복구용
 
     if (!isBossDeath) {
       // 레벨 기반 장비 손실 확률 계산
-      // Lv 1~5: 0%, Lv 6: 10%, Lv 10: 50%, Lv 15+: 100%
+      // Lv 1: 20%, Lv 5: ~56%, Lv 10+: 100%
+      // 공식: 20 + (level - 1) * 80 / 9
       final level = state.traits.level;
-      final lossChancePercent = ((level - 5) * 10).clamp(0, 100);
+      final lossChancePercent = level >= 10
+          ? 100
+          : (20 + ((level - 1) * 80 ~/ 9)).clamp(0, 100);
       final roll = state.rng.nextInt(100); // 0~99
       final shouldLoseEquipment = roll < lossChancePercent;
 
@@ -1004,10 +1008,10 @@ class ProgressService {
               )];
 
           // 제물로 바칠 아이템 정보 저장
-          final lostItem = state.equipment.getItemByIndex(sacrificeIndex);
+          lostEquipmentItem = state.equipment.getItemByIndex(sacrificeIndex);
-          lostItemName = lostItem.name;
+          lostItemName = lostEquipmentItem.name;
           lostItemSlot = EquipmentSlot.values[sacrificeIndex];
-          lostItemRarity = lostItem.rarity;
+          lostItemRarity = lostEquipmentItem.rarity;
 
           // 해당 슬롯을 빈 장비로 교체
           newEquipment = newEquipment.setItemByIndex(
@@ -1029,6 +1033,7 @@ class ProgressService {
       lostItemName: lostItemName,
       lostItemSlot: lostItemSlot,
       lostItemRarity: lostItemRarity,
+      lostItem: lostEquipmentItem, // 광고 부활 시 복구용
       goldAtDeath: state.inventory.gold,
       levelAtDeath: state.traits.level,
       timestamp: state.skillSystem.elapsedMs,