The policy must ALLOW Anubis's own endpoints before the challenge-all rule
or the challenge challenges itself: browsers POST-solve via make-challenge
then GET-navigate pass-challenge, and a challenged answer renders as the
browser's own fetch-failure error page. Non-JS clients never reach the
verify step, which is why every curl probe looked green while every human
hit a wall. Also records that v1.13.0's valid action verbs are
ALLOW/CHALLENGE/DENY (ACCEPT crash-looped the unit on first deploy).