Cap how many Whisper transcription jobs each user account can start per
rolling window (day/week/month), configurable from admin settings. The
player modal shows remaining usage and the server returns 429 with
details when the limit is hit.
Enforcement is atomic with the job insert (per-user advisory lock, same
pattern as media-request quotas), so concurrent requests cannot race
past the limit. Failed/cancelled jobs that never produced transcription
work are refunded. Exemption applies to the admin account's primary
profile only; other profiles on an admin account stay subject to the
quota. A partial index covers the quota count, a malformed quota
setting row degrades to "no quota" instead of blocking startup, and the
period vocabulary and admin-role predicate are each defined once
(ai.ValidQuotaPeriod, apimw.IsAdmin).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
