feat(nostr): publish the active ticket wave, not the roll-up

Since upstream v1.6.8 price, currency and inventory belong to time-boxed
ticket waves, and the event-level fields `sync_event_ticket_waves`
derives are the PRIMARY wave's price/currency and the SUM of every
wave's stock. The NIP-52 publisher read those, so as soon as an
organiser created a second wave the public card would advertise the
early-bird price after early bird closed and count stock in waves that
had not opened. Refs #61.

`build_nip52_event` now describes the wave a buyer can actually buy
from:

- several waves can be open at once, and a publisher has no one to ask
  which one the buyer wants (the purchase endpoint errors with "Please
  select a ticket wave"), so it advertises the CHEAPEST open wave — the
  price a buyer is able to obtain. Deviation recorded in
  docs/upstream-candidates.md.
- with no open wave, `tickets_available` is 0 and never omitted:
  omission used to mean "unlimited", which #34/#62 removed as a concept.
- `tickets_payment_methods` is scoped to the advertised wave too. It was
  derived from `event.allow_fiat` — the primary wave's — so it could
  offer a fiat rail while `tickets_allow_fiat` was absent and the
  purchase endpoint would refuse it. They are the same fact and now come
  from the same place.

Wave boundaries are time-driven, and every republish we have is
sale-driven, so nothing fires when early bird ends at midnight. Rather
than add a scheduler, a publish records which wave it advertised
(`nostr_published_wave_id`, m004) and the reconciliation sweep compares
that against the wave that would be advertised now, setting
`nostr_publish_pending` on a mismatch — reusing the existing retry path.
NULL means "never published", which the sweep leaves alone so an upgrade
does not republish the whole table on first boot.

The selection rule lives in `models.advertised_ticket_wave` so the
publisher and the drift detector cannot disagree about what is on the
relay.

17 new tests; 114 pass. ruff, black, prettier clean; mypy error set
still identical to HEAD's baseline.

nostr_hooks.py

@@ -8,7 +8,7 @@ import cycle (views_api -> nostr_hooks -> nostr_publisher -> models).
 from loguru import logger
 
 from .crud import update_event
-from .models import Event
+from .models import Event, advertised_wave_key
 from .nostr_publisher import publish_event_to_nostr
 
 
@@ -72,6 +72,11 @@ async def publish_or_delete_nostr_event(event: Event, *, delete: bool = False) -
         if not delete:
             event.nostr_event_id = nostr_event.id
             event.nostr_event_created_at = nostr_event.created_at
+            # Record which wave this publish advertised so the sweep can
+            # notice a wave boundary later (aiolabs/events#61). Written in
+            # the same update as the cleared flag, so the two can never
+            # disagree about what is on the relay.
+            event.nostr_published_wave_id = advertised_wave_key(event)
         await update_event(event)
         return True
     except Exception as exc: