Why, and what was tried
The session raising this recommends: Approve 138c1dbe on GitHub
Bot 🟢 LGTM on this exact head; 3 small ci.yml hunks + a 30-line script that fails loud (missing file / not-sharded plan); the shard handoff upload runs AFTER the step (line 2725 vs 2694) and the drift tests pin that order with mutation controls; the shards still verify count on arrival so a bug reads red, never false green; CI-only, no prod surface. Same files tested, shards start ~8-10 min sooner for +3-4 runner-min.
Tried first, unsuccessfully: Smith is unattended and may not merge or approve a dangerous-diff PR; the merge-hold check needs a GitHub approval of this exact commit by a person other than the author (fede-propflow). I read every ci.yml hunk, the new script, the 4 test files, the step/upload ordering at the head SHA, and the bot's verdict — nothing left that a model can settle.
f581c8e1 is parked on this.