fix(hamster-ball-bukkit): 修正PlaceholderAPI变量

hamster-ball-bukkit/src/main/java/cn/hamster3/mc/plugin/ball/bukkit/HamsterBallPlugin.java

@@ -45,12 +45,6 @@ public class HamsterBallPlugin extends JavaPlugin {
             });
             return;
         }
-        if (Bukkit.getPluginManager().isPluginEnabled("PlaceholderAPI")) {
-            PlaceholderHook.INSTANCE.register();
-            logger.info("已挂载 PlaceholderAPI 变量!");
-        } else {
-            logger.warning("服务器未安装 PlaceholderAPI, 取消挂载变量!");
-        }
         Bukkit.getPluginManager().registerEvents(BallBukkitListener.INSTANCE, this);
         logger.info("已注册 BallBukkitListener.");
         BallAPI.getInstance().sendBallMessage(
@@ -59,6 +53,12 @@ public class HamsterBallPlugin extends JavaPlugin {
                 new ServerOnlineEvent(BallAPI.getInstance().getLocalServerInfo())
         );
         logger.info("HamsterBall 已启动.");
+        sync(() -> {
+            if (Bukkit.getPluginManager().isPluginEnabled("PlaceholderAPI")) {
+                PlaceholderHook.INSTANCE.register();
+                logger.info("已挂载 PlaceholderAPI 变量!");
+            }
+        });
     }
 
     @Override