The registration gate, once it resolves the authenticated subject to a tapir
user_id, calls StampLogin (store-throttled to one row per user per day). Best-
effort: a stamp failure is logged and swallowed so it never breaks the request.
This is what makes the read-side Stage-0 usage signal actually accrue.
Tests cover the happy-path stamp, the same-day throttle, and that an
unregistered subject (redirected to /register) is never stamped.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
mathiasandClaude Opus 4.8
2fac735837