swarm-authelia-bridge answered one 401 for four causes, including its own
client credentials being rejected by authelia — telling a caller its token
was invalid when the fault was ours. That cost a real diagnostic round-trip,
because the only thing separating the two was a log line inside a container.
Introspection now returns a three-way Verdict, and one classify() maps it to
either admission, a 401 (the caller's credential) or a 503 (ours). Admission
is unchanged: Ok is reachable from exactly one variant.
