Organizers pick which rails an event accepts — Lightning, card (fiat) or
both — instead of a bare "allow fiat" toggle. `extra.payment_methods`
uses the field name upstream v2 (lnbits/events#64) introduces so the
eventual rebase merges cleanly; an empty list keeps the legacy rule
(Lightning always, fiat when allow_fiat), and allow_fiat stays the
fiat-currency carrier, kept in lockstep on save. The effective list is
published as the NIP-52 tag `tickets_payment_methods` so clients render
exactly the buttons the purchase endpoint will accept, and the buyer page
defaults to the first accepted rail (a card-only event never submits
"lightning").
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EYwoAkZZmXMMmaBp4WGUBo
