feat(core): 장비 시스템 및 게임 상태 모델 확장

- Equipment 클래스를 11개 슬롯으로 확장 (원본 Main.dfm 충실)
- TaskInfo에 몬스터 정보(baseName, part) 추가
- Stats에 현재 HP/MP 필드 추가
- 히스토리 기능 구현 (plotHistory, questHistory)
- pq_logic winEquip/winStatIndex 원본 로직 개선
- 퀘스트 몬스터 처리 로직 구현
- SaveData 직렬화 확장

lib/src/core/model/save_data.dart

@@ -63,6 +63,8 @@ class GameSave {
         'cha': stats.cha,
         'hpMax': stats.hpMax,
         'mpMax': stats.mpMax,
+        'hpCurrent': stats.hpCurrent,
+        'mpCurrent': stats.mpCurrent,
       },
       'inventory': {
         'gold': inventory.gold,
@@ -73,7 +75,15 @@ class GameSave {
       'equipment': {
         'weapon': equipment.weapon,
         'shield': equipment.shield,
-        'armor': equipment.armor,
+        'helm': equipment.helm,
+        'hauberk': equipment.hauberk,
+        'brassairts': equipment.brassairts,
+        'vambraces': equipment.vambraces,
+        'gauntlets': equipment.gauntlets,
+        'gambeson': equipment.gambeson,
+        'cuisses': equipment.cuisses,
+        'greaves': equipment.greaves,
+        'sollerets': equipment.sollerets,
         'bestIndex': equipment.bestIndex,
       },
       'spells': spellBook.spells
@@ -88,9 +98,23 @@ class GameSave {
         'taskInfo': {
           'caption': progress.currentTask.caption,
           'type': progress.currentTask.type.name,
+          'monsterBaseName': progress.currentTask.monsterBaseName,
+          'monsterPart': progress.currentTask.monsterPart,
         },
         'plotStages': progress.plotStageCount,
         'questCount': progress.questCount,
+        'plotHistory': progress.plotHistory
+            .map((e) => {'caption': e.caption, 'complete': e.isComplete})
+            .toList(),
+        'questHistory': progress.questHistory
+            .map((e) => {'caption': e.caption, 'complete': e.isComplete})
+            .toList(),
+        'questMonster': progress.currentQuestMonster != null
+            ? {
+                'data': progress.currentQuestMonster!.monsterData,
+                'index': progress.currentQuestMonster!.monsterIndex,
+              }
+            : null,
       },
       'queue': queue.entries
           .map(
@@ -134,6 +158,8 @@ class GameSave {
         cha: statsJson['cha'] as int? ?? 0,
         hpMax: statsJson['hpMax'] as int? ?? 0,
         mpMax: statsJson['mpMax'] as int? ?? 0,
+        hpCurrent: statsJson['hpCurrent'] as int?,
+        mpCurrent: statsJson['mpCurrent'] as int?,
       ),
       inventory: Inventory(
         gold: inventoryJson['gold'] as int? ?? 0,
@@ -149,7 +175,15 @@ class GameSave {
       equipment: Equipment(
         weapon: equipmentJson['weapon'] as String? ?? 'Sharp Stick',
         shield: equipmentJson['shield'] as String? ?? '',
-        armor: equipmentJson['armor'] as String? ?? '',
+        helm: equipmentJson['helm'] as String? ?? '',
+        hauberk: equipmentJson['hauberk'] as String? ?? '',
+        brassairts: equipmentJson['brassairts'] as String? ?? '',
+        vambraces: equipmentJson['vambraces'] as String? ?? '',
+        gauntlets: equipmentJson['gauntlets'] as String? ?? '',
+        gambeson: equipmentJson['gambeson'] as String? ?? '',
+        cuisses: equipmentJson['cuisses'] as String? ?? '',
+        greaves: equipmentJson['greaves'] as String? ?? '',
+        sollerets: equipmentJson['sollerets'] as String? ?? '',
         bestIndex: equipmentJson['bestIndex'] as int? ?? 0,
       ),
       spellBook: SpellBook(
@@ -178,6 +212,15 @@ class GameSave {
         ),
         plotStageCount: progressJson['plotStages'] as int? ?? 1,
         questCount: progressJson['questCount'] as int? ?? 0,
+        plotHistory: _historyListFromJson(
+          progressJson['plotHistory'] as List<dynamic>?,
+        ),
+        questHistory: _historyListFromJson(
+          progressJson['questHistory'] as List<dynamic>?,
+        ),
+        currentQuestMonster: _questMonsterFromJson(
+          progressJson['questMonster'] as Map<String, dynamic>?,
+        ),
       ),
       queue: QueueState(
         entries: Queue<QueueEntry>.from(
@@ -233,5 +276,29 @@ TaskInfo _taskInfoFromJson(Map<String, dynamic> json) {
     (t) => t.name == typeName,
     orElse: () => TaskType.neutral,
   );
-  return TaskInfo(caption: json['caption'] as String? ?? '', type: type);
+  return TaskInfo(
+    caption: json['caption'] as String? ?? '',
+    type: type,
+    monsterBaseName: json['monsterBaseName'] as String?,
+    monsterPart: json['monsterPart'] as String?,
+  );
+}
+
+List<HistoryEntry> _historyListFromJson(List<dynamic>? json) {
+  if (json == null || json.isEmpty) return [];
+  return json.map((e) {
+    final m = e as Map<String, dynamic>;
+    return HistoryEntry(
+      caption: m['caption'] as String? ?? '',
+      isComplete: m['complete'] as bool? ?? false,
+    );
+  }).toList();
+}
+
+QuestMonsterInfo? _questMonsterFromJson(Map<String, dynamic>? json) {
+  if (json == null) return null;
+  return QuestMonsterInfo(
+    monsterData: json['data'] as String? ?? '',
+    monsterIndex: json['index'] as int? ?? -1,
+  );
 }