The committed duration seed is recorded on fast CI; a syscall-supervised
sandbox replays the same files 2-4x slower. Observed post-merge: a 253-file
shard predicted ~242s was wall-killed at its predicted-x3 725s wall while
genuinely progressing (the old count heuristic guaranteed 1265s). Packed
walls may be looser than the count floor, never tighter.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>