Fix M4A fallback ingestion

backend/src/main/java/com/music/service/DedupService.java

@@ -9,6 +9,7 @@ import org.jaudiotagger.tag.Tag;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.messaging.simp.SimpMessagingTemplate;
+import com.music.config.AsyncConfig;
 import org.springframework.scheduling.annotation.Async;
 import org.springframework.stereotype.Service;
 
@@ -52,7 +53,7 @@ public class DedupService {
     /**
      * 异步执行去重任务
      */
-    @Async
+    @Async(AsyncConfig.TASK_EXECUTOR_BEAN_NAME)
     public void dedup(String taskId,
                       String libraryDir,
                       String trashDir,