Login error banner: 'unknown or already used code' after navigating to a ticket

Creator (2026-09-24): logged in as Archi Tect, on a ticket page a red banner top left says ident refused the login (400: unknown or already used code).

Architect's hypothesis (to be reproduced first, not assumed): login.js runs again on in-app navigation and adds a second ident-login listener to the persistent selector, so one selection triggers two exchanges with the same one-time code; the second fails and sets the banner although the first logged the user in. Fix + a gate check: navigate list -> ticket, then select an identity, no error banner, exactly one exchange.

Creator's follow-up: logged in as themselves (the creator identity) the banner does NOT appear; only as the second identity Archi Tect. So the path to the second identity matters (switching identities in the selector while logged in? log out + select? login button?) - reproduce exactly that path; the double-listener hypothesis alone would affect every identity.

Path (creator): logged in as the creator identity -> clicked 'Log out' -> opened the selector -> chose Archi Tect -> banner. Reproduce exactly this (log out, then select another identity), on a ticket page and on the list.