update slot resume pointers for step 1816

slots/4/latest.json

@@ -1 +1 @@
-{"worker_id": "slot:4", "checkpoint": "slots/4/checkpoint-615", "step": 615, "updated_at": 1776393936}
+{"worker_id": "slot:4", "checkpoint": "slots/4/checkpoint-1816", "step": 1816, "updated_at": 1776405330}