refactor(ui): 물약 글로벌 쿨타임 적용 UI 정리

- usedPotionTypes/usedInBattle 파라미터 제거
- 전투당 타입별 제한 → 시간 기반 쿨타임 전환
- PotionInventoryPanel 불투명도 로직 제거

lib/src/features/game/pages/inventory_page.dart

@@ -16,13 +16,11 @@ class InventoryPage extends StatelessWidget {
     required this.inventory,
     required this.potionInventory,
     required this.encumbrance,
-    this.usedPotionTypes = const {},
   });
 
   final Inventory inventory;
   final PotionInventory potionInventory;
   final ProgressBarState encumbrance;
-  final Set<PotionType> usedPotionTypes;
 
   @override
   Widget build(BuildContext context) {
@@ -41,7 +39,6 @@ class InventoryPage extends StatelessWidget {
           flex: 2,
           child: PotionInventoryPanel(
             inventory: potionInventory,
-            usedInBattle: usedPotionTypes,
           ),
         ),