Authelia (and many other IdPs) only put `sub` in the ID token by
default, surfacing `preferred_username`/`email`/`groups` from the
userinfo endpoint. Fetch userinfo after id_token verification and
fold its claims into the parsed claim map; the id_token claims
remain authoritative on conflict so the signed assertion still
wins.
Live sweep against https://auth.dcglab.co.uk verified all four
flows: rm-admin → admin JIT, rm-operator → operator JIT (RBAC
denies admin pages), rm-viewer → viewer JIT (RBAC denies operator
pages), rm-other → no_role_match banner with no row created.
Returning rm-admin sign-in resolves to the same row by sub.
Screenshots in _diag/p4-05-sweep/.