update slot resume pointers for step 487

slots/4/latest.json

@@ -1 +1 @@
-{"worker_id": "slot:4", "checkpoint": "slots/4/checkpoint-340", "step": 340, "updated_at": 1776357898}
+{"worker_id": "slot:4", "checkpoint": "slots/4/checkpoint-487", "step": 487, "updated_at": 1776388239}