Saving the connection showed an error that a refresh then cleared. The effect
that re-mints the frame session re-ran, but `state` was left at 'ready' from
the previous pass — so the iframe mounted immediately, before the cookie
existed, and the first request inside it answered 401. By the time anyone
refreshed, the mint had finished.
A stale 'ready' is worse than a spinner: it renders something broken
confidently.
Also stays on the form after the URL-only step, where there is still a token to
set. Bouncing to a frame that immediately sends you back is worse than not
moving.