Report Builder Credential

What the daily credential probe found (rooster-credential-check.yml), and -- the only caller actually present in this repository as of this build -- tools/rooster_worker/drain.py's own seat_is_alive preflight: the build seat itself, checked BEFORE anything is claimed.

Presence is not validity: the probe makes a real authenticated call, because /api/health once reported the Anthropic key live over a revoked one. A failure raises one action item naming the secret to replace; a later success clears it.

THIS IS ALSO WHERE THE WHOLE QUEUE LEARNS THE SEAT IS DOWN. Frederick, 2026-08-11, on the Mac-hosted build seat sleeping overnight: "the issue just stays filed... the team knows the developer has the flu; the work is not lost and nobody is guessing." seat_is_alive's own preflight already refuses to CLAIM anything while the seat is down (protecting build_attempts), but on its own that is invisible on any individual issue's own record. A failed probe here stamps every issue already queued with build_unreachable_since/_detail (mark_build_queue_unreachable) so a person looking at any one of them sees "queued, seat offline since 9pm" instead of a row that simply never moves; a healthy probe clears it (clear_build_queue_unreachable) the moment the seat answers again. Best-effort: a failure marking/ clearing the queue must not turn a real credential result into a 500 -- the credential card above is still the authoritative signal either way.