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

test/core/util/pq_logic_test.dart

@@ -1,4 +1,3 @@
-import 'package:askiineverdie/src/core/model/equipment_slot.dart';
 import 'package:askiineverdie/src/core/model/game_state.dart';
 import 'package:askiineverdie/src/core/model/pq_config.dart';
 import 'package:askiineverdie/src/core/util/deterministic_random.dart';
@@ -65,7 +64,7 @@ void main() {
         config,
         DeterministicRandom(12),
         5,
-        EquipmentSlot.weapon,
+        0, // weapon slot
       ),
       'Baselard',
     );
@@ -74,7 +73,7 @@ void main() {
         config,
         DeterministicRandom(15),
         2,
-        EquipmentSlot.armor,
+        2, // helm slot (armor category)
       ),
       '-2 Canvas',
     );
@@ -86,18 +85,35 @@ void main() {
   });
 
   test('monsterTask picks level-appropriate monsters with modifiers', () {
-    expect(
-      pq_logic.monsterTask(config, DeterministicRandom(99), 5, null, null),
-      'an underage Rakshasa',
+    final result1 = pq_logic.monsterTask(
+      config,
+      DeterministicRandom(99),
+      5,
+      null,
+      null,
     );
-    expect(
-      pq_logic.monsterTask(config, DeterministicRandom(7), 10, null, null),
-      'a greater Sphinx',
+    expect(result1.displayName, 'an underage Rakshasa');
+    expect(result1.baseName, 'Rakshasa');
+    expect(result1.part, isNotEmpty);
+
+    final result2 = pq_logic.monsterTask(
+      config,
+      DeterministicRandom(7),
+      10,
+      null,
+      null,
     );
-    expect(
-      pq_logic.monsterTask(config, DeterministicRandom(5), 6, 'Goblin|3', 3),
-      'a Barbed Devil',
+    expect(result2.displayName, 'a greater Sphinx');
+    expect(result2.baseName, 'Sphinx');
+
+    final result3 = pq_logic.monsterTask(
+      config,
+      DeterministicRandom(5),
+      6,
+      'Goblin|3|ear',
+      3,
     );
+    expect(result3.displayName, 'a Barbed Devil');
   });
 
   test('completeQuest and completeAct return deterministic results', () {