The screen takes no input: the login answer's entrypoint values reach it as a
process handoff (TwoFactorTickets.handOffApproval), never as an edge
argument a trail would carry. A retrace of the two-factor chain in a fresh
process therefore needs that handoff as a precondition; carrying a pending
challenge across processes is the checkpoint work (#314).
The screen takes no input: the login answer's entrypoint values reach it as a process handoff (
TwoFactorTickets.handOffApproval), never as an edge argument a trail would carry. A retrace of the two-factor chain in a fresh process therefore needs that handoff as a precondition; carrying a pending challenge across processes is the checkpoint work (#314).