feat: per-operator settings — house rules + card acceptance (multi-tenant)

Chatelet is multi-tenant: any LNbits user can host rooms. What an operator
decides for all their rooms now lives in chatelet.operator_settings, keyed
by user id and created lazily (m003, which also indexes bookings by guest):
check-in/out times, cancellation policy, and accept_fiat.

Guests see it: the public room view (both doors) gains house_rules and
payment_methods, and the kind:30402 listing carries payment_methods,
checkin_time and checkout_time tags so a generic Nostr client can render
the right pay buttons and rules without our RPC. The check-in DM reads the
room owner's rules instead of the instance row.

Card is offered only when the operator opted in, the room is fiat-priced,
and LNbits core has a fiat provider for that user — resolved through
settings.get_fiat_providers_for_user(owner), the one seam lnbits#67's
per-user Stripe credentials will plug into; chatelet never sees creds.

Operator endpoints: GET/PUT /api/v1/operator (admin key → wallet user) and
RPC twins chatelet_operator_get/update (AUTH_WALLET); saving re-publishes
the owner's active listings. Admin UI moves the house-rule inputs into a
per-operator card with the card toggle and a provider hint. The old
house-rule columns on settings stay for old rows but are no longer read.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tasks.py

@@ -12,7 +12,7 @@ from lnbits.core.models import Payment
 from lnbits.tasks import register_invoice_listener
 from loguru import logger
 
-from . import crud
+from . import crud, services
 from .models import BookingStatus
 from .nostr import service as nostr
 
@@ -47,9 +47,11 @@ async def on_invoice_paid(payment: Payment):
     # Best-effort: a publish failure must not undo a confirmed, paid booking.
     try:
         room = await crud.get_room(booking.room_id)
-        settings = await crud.get_or_create_settings()
         if room:
-            await nostr.send_checkin_dm(booking, room, settings)
+            # House rules are the room owner's, not the instance's.
+            owner = await services.room_owner_id(room)
+            ops = await crud.get_or_create_operator_settings(owner)
+            await nostr.send_checkin_dm(booking, room, ops)
     except Exception as exc:  # noqa: BLE001
         logger.warning(f"chatelet: check-in DM failed for {booking.id} (continuing): {exc}")