feat(养成系统): 实现局外养成等级机制并调整升级消耗

添加upgradableFieldsLevel字段记录养成等级
修改升级逻辑使用等级计算消耗而非固定倍率
升级时自动增加等级并重新计算下次升级消耗

scripts/Statemachine/FieldShow.gd

@@ -29,6 +29,9 @@ func _ready():
 		func():
 			if upgradable:
 				if enoughToUpgrade():
+					for index in costItems:
+						var item = costItems[index]
+						OutGameStorage.inventory[item] -= costCounts[index]
 					value += upgradeValue
 					upgrade.emit(value)
 					rebuildInfo()