feat(保存系统): 实现游戏存档功能

添加SaveEngine类用于处理游戏存档的序列化、加载和应用
修改GameBusManager在游戏重启时自动保存和加载存档
扩展JsonTool功能以支持文件解析和字符串序列化
更新StarterPanel添加教程观看状态保存

scripts/Tools/Engines/SaveEngine.gd

@@ -0,0 +1,23 @@
+class_name SaveEngine
+
+const SAVE_FILE = "user://save.json"
+
+static func serialize():
+	return {
+		"out-game": {
+			"value": OutGameStorage.upgradableFieldsValue.duplicate(),
+			"level": OutGameStorage.upgradableFieldsLevel.duplicate()
+		},
+		"tutorial-watched": StarterPanel.tutorialWatched
+	}
+static func apply(saveData: Dictionary):
+	OutGameStorage.upgradableFieldsValue = saveData["out-game"]["value"]
+	OutGameStorage.upgradableFieldsLevel = saveData["out-game"]["level"]
+	StarterPanel.tutorialWatched = saveData["tutorial-watched"]
+static func load():
+	return JsonTool.parseFromFile(SAVE_FILE)
+static func save():
+	var file = FileAccess.open(SAVE_FILE, FileAccess.ModeFlags.WRITE)
+	if file is FileAccess:
+		file.store_string(JsonTool.stringify(serialize()))
+		file.close()