The per-request SELECT users WHERE uuid=? in require_role was the
hidden tax behind every authed endpoint — it kept _execute at ~60%
across the profile even after the page caches landed. Even /health
(with its DB and Docker probes cached) was still 52% _execute from
this one query.
- dependencies.py: 10s TTL cache on get_user_by_uuid, well below JWT
expiry. invalidate_user_cache(uuid) is called on password change,
role change, and user delete.
- api_get_config.py: 5s TTL cache on the admin branch's list_users()
(previously fetched every /config call). Invalidated on user
create/update/delete.
- api_change_pass.py + api_manage_users.py: invalidation hooks on
all user-mutating endpoints.