仓库组件 + 防御塔升级

- `PlayerInventoryComponent`：玩家库存组件，收集金币/组件/防御塔等道具
- 补全防御塔的升级逻辑，最高 5 级

Assets/GameMain/Scripts/UI/Combat/Controller/CombatSelectFormController.cs

@@ -98,10 +98,12 @@ namespace GeometryTD.UI
             switch (userData.ClickObjectType)
             {
                 case CombatSelectClickObjectType.Foundation:
+                    _useCase.SetUpgradeVisible(true);
                     _useCase.ShowForFoundation(userData.ContentPosition);
                     break;
                 case CombatSelectClickObjectType.Tower:
                     _useCase.SetUpgradePrice(userData.UpgradeCost);
+                    _useCase.SetUpgradeVisible(!userData.IsTowerAtMaxLevel);
                     _useCase.SetDestroyGain(userData.DestroyGain);
                     _useCase.ShowForTower(userData.ContentPosition);
                     break;
@@ -133,6 +135,7 @@ namespace GeometryTD.UI
                 return null;
             }
 
+            _useCase.SetUpgradeVisible(true);
             _useCase.ShowForFoundation(contentPosition);
             return OpenUI(_useCase.TryRefresh());
         }
@@ -146,6 +149,7 @@ namespace GeometryTD.UI
             }
 
             _useCase.SetUpgradePrice(upgradeCost);
+            _useCase.SetUpgradeVisible(true);
             _useCase.SetDestroyGain(destroyGain);
             _useCase.ShowForTower(contentPosition);
             return OpenUI(_useCase.TryRefresh());