feat(多人游戏): 添加玩家名称存储并优化多人游戏逻辑

在MultiplayerState中添加playerName静态变量用于存储玩家名称
修改Starter.gd中的startMultiplayerGame方法，保存玩家名称到MultiplayerState
优化EntityBase.gd的AI逻辑，仅当玩家名称匹配时才执行AI
移除不再需要的多人游戏同步方法

scripts/Contents/Panels/Starter.gd

@@ -53,11 +53,11 @@ func rebuildAllPlayers(playerNames: Array[String]):
 		addPlayerName(i)
 @rpc("any_peer")
 func startMultiplayerGame():
-	if multiplayer.is_server():
-		for i in getPlayerNames():
-			EntityBase.generatePlayer(i)
-		Wave.next()
-		UIState.closeCurrentPanel()
+	MultiplayerState.playerName = playerNameInput.text
+	for i in getPlayerNames():
+		EntityBase.generatePlayer(i)
+	Wave.next()
+	UIState.closeCurrentPanel()
 
 func _ready():
 	historyStack = Composables.useHistoryStack(playerNameInput)