cache.sx — a process wrapping the token registry, memoising introspect.
Revocation stays real via generation invalidation: any revoke/refresh bumps
a generation counter, so every cached positive instantly becomes a miss and
re-validates against the live registry. A revoked token never reads valid
out of cache, not for a millisecond. stats() exposes hits/misses. New
tests/cache.sx. 101/101.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
