update slot resume pointers for step 501

slots/12/latest.json

@@ -1 +1 @@
-{"worker_id": "slot:12", "checkpoint": "slots/12/checkpoint-389", "step": 389, "updated_at": 1776359973}
+{"worker_id": "slot:12", "checkpoint": "slots/12/checkpoint-501", "step": 501, "updated_at": 1776388785}