Function decide_admission 

pub fn decide_admission(door: Door, pairing: Pairing) -> Admission

Decides whether one HTTP request may reach the work behind a door, once Keys::pairing has judged what it offered.

The one place an HTTP caller’s credential decides a door. Every face demands a key, so a caller with nothing is turned away from the three doors that act wherever the city listens.

Door::Acp is admitted without one on purpose: what an unauthenticated editor may learn is agent_protocols::admit’s to word, and it words it so that a stranger learns exactly one bit.