Both tests in export.spec.ts are still named "ZIP download 404s…" but now
assert only that `/export/ticket` refuses. That move was right — the mint
pre-validates, and refusing there spends none of the guest's three daily
downloads — but it left `resolve_export_file` unasserted on the download path
itself, so deleting that check would not have turned anything red.
It cannot be covered by minting against an already-dead archive, because the
mint refuses first. The order has to be: real release → mint while healthy →
retire the generation → download. Which is also precisely what happens to a
ticket already in flight when the host takes a photo down mid-download.
Carries its own positive control: the ticket is asserted to serve a 200 before
the epoch moves, so the 404 afterwards cannot be green for the wrong reason —
an expired or never-valid ticket would 404 too.
