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>

tests/conftest.py

@@ -86,3 +86,23 @@ def make_request(
         check_out=check_out,
         num_guests=num_guests,
     )
+
+
+def patch_owner(monkeypatch, *, user_id="u1", accept_fiat=False, providers=()):
+    """Route the public room view away from the core DB: rooms belong to
+    `user_id`, whose operator settings are fresh defaults (+ accept_fiat) and
+    who has `providers` enabled in LNbits core."""
+    from types import SimpleNamespace
+
+    from .. import crud, services
+    from ..models import OperatorSettings
+
+    async def get_wallet(_wallet_id):
+        return SimpleNamespace(user=user_id)
+
+    async def ops(uid):
+        return OperatorSettings(user_id=uid, accept_fiat=accept_fiat)
+
+    monkeypatch.setattr(services, "get_wallet", get_wallet)
+    monkeypatch.setattr(crud, "get_or_create_operator_settings", ops)
+    monkeypatch.setattr(services, "fiat_providers_for_user", lambda _uid: list(providers))