fix: objective改在SERVER_STARTED创建（scoreboard load完成后）

轮询线程比scoreboard.load更早跑，仍会撞名崩溃。改用ServerLifecycleEvents.SERVER_STARTED。

src/main/java/com/github/zly2006/carpetslsaddition/ServerMain.java

@@ -57,6 +57,12 @@ public class ServerMain implements ModInitializer, CarpetExtension {
         startBoardWatcher(server);
     }
 
+    /** 服务器完全启动后创建 objective（此时 scoreboard 已 load 完，避免重名崩溃）。 */
+    static {
+        net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents.SERVER_STARTED.register(server ->
+                com.github.zly2006.carpetslsaddition.util.BoardManager.ensureObjectives(server));
+    }
+
     /** 每秒检测 slsBoardEnabled 规则变化并同步给客户端。 */
     private void startBoardWatcher(MinecraftServer server) {
         Thread t = new Thread(() -> {

src/main/java/com/github/zly2006/carpetslsaddition/util/BoardManager.java

@@ -74,15 +74,9 @@ public final class BoardManager {
         access.set(value);
     }
 
-    private static boolean objectivesEnsured = false;
-
     /** 从 stats 同步所有在线玩家的分数到 scoreboard（定期调用）。 */
     public static void syncScores(MinecraftServer server) {
         Scoreboard sb = server.getScoreboard();
-        if (!objectivesEnsured) {
-            ensureObjectives(server);
-            objectivesEnsured = true;
-        }
         Objective deaths = sb.getObjective(OBJ_DEATHS);
         Objective mined = sb.getObjective(OBJ_MINED);
         if (deaths == null && mined == null) {