update slot resume pointers for step 8139

slots/12/latest.json

@@ -1 +1 @@
-{"worker_id": "slot:12", "checkpoint": "slots/12/checkpoint-6232", "step": 6232, "updated_at": 1776441511}
+{"worker_id": "slot:12", "checkpoint": "slots/12/checkpoint-8139", "step": 8139, "updated_at": 1776469357}