events/docs/upstream-candidates.md

Upstream PR candidates

Running log of fork features that are shaped so they could be offered to lnbits/events (or lnbits/lnbits). Add a row whenever a change lands here in an upstream-compatible form; strike it when the PR merges upstream.

Feature	Where	Upstream target	Readiness
frontend_url + origin allow-list + ?checkout= return contract	views_api.py _resolve_frontend_root, api_ticket_create	lnbits/events	after the #33 rebase, as a small PR
Ticket ids minted before the invoice so success_url can carry them	api_ticket_create	lnbits/events	ships with the above
extra.checkout (success/cancel URL, customer_email, line item, metadata) on fiat purchases	api_ticket_create	lnbits/events (needs lnbits StripeCheckoutOptions.cancel_url/customer_email, PR'd from aiolabs/lnbits)	with the lnbits patch
extra.payment_methods per event + tickets_payment_methods NIP-52 tag	models.py, nostr_publisher.py	lnbits/events (v2 PR #64 introduces the same field)	offer as review input on #64
asyncio.to_thread around the smtplib send	services.py _send_ticket_email_notification	lnbits/events	trivial, standalone
QR logo overlay in make_qr_png (instance lnbits_qr_logo)	views_api.py	lnbits/events	standalone
Multi-ticket purchase as N rows on one payment_hash	api_ticket_create, crud.py	lnbits/events	overlaps v2 baskets; review input on #64
Free tickets without minting an invoice	_issue_free_tickets	lnbits/events	small, standalone
NIP-52 publishing + approval workflow	nostr_*.py, views_api.py	lnbits/events #46	open; rebase onto v1.6.8