fix download

src/server/services/download_service.py

@@ -586,6 +586,30 @@ class DownloadService:
         
         return count
 
+    async def clear_failed(self) -> int:
+        """Clear failed downloads from history.
+
+        Returns:
+            Number of items cleared
+        """
+        count = len(self._failed_items)
+        self._failed_items.clear()
+        logger.info("Cleared failed items", count=count)
+        
+        # Broadcast queue status update
+        if count > 0:
+            queue_status = await self.get_queue_status()
+            await self._broadcast_update(
+                "queue_status",
+                {
+                    "action": "failed_cleared",
+                    "cleared_count": count,
+                    "queue_status": queue_status.model_dump(mode="json"),
+                },
+            )
+        
+        return count
+
     async def retry_failed(
         self, item_ids: Optional[List[str]] = None
     ) -> List[str]: