feat(多人游戏): 添加连接状态检查和断开连接功能

- 在MultiplayerState中添加isConnected方法检查连接状态
- 修改launchServer和connectClient方法以更新连接状态
- 在Starter面板中添加断开连接按钮并实现状态同步
- 更新UI显示连接状态和颜色

scripts/Tools/Managers/MultiplayerState.gd

@@ -25,8 +25,15 @@ static var isMultiplayer: bool = false
 
 static var maxPlayer: int = 10
 
+static func isConnected():
+	return [ConnectionState.CONNECTED_HOST, ConnectionState.CONNECTED_CLIENT].has(state)
 static func launchServer(port: int):
-	isMultiplayer = true
 	var peer = ENetMultiplayerPeer.new()
 	peer.create_server(port, maxPlayer)
+	state = ConnectionState.CONNECTED_HOST
+	return peer
+static func connectClient(host: String, port: int):
+	var peer = ENetMultiplayerPeer.new()
+	peer.create_client(host, port)
+	state = ConnectionState.CONNECTED_CLIENT
 	return peer