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>

migrations.py

@@ -123,3 +123,27 @@ async def m002_room_checkin_instructions(db):
         "ALTER TABLE chatelet.rooms ADD COLUMN checkin_instructions TEXT "
         "NOT NULL DEFAULT '';"
     )
+
+
+async def m003_operator_settings_and_guest_index(db):
+    """Chatelet is multi-tenant: every LNbits user may host rooms. What an
+    operator decides for *all their rooms* — house rules and whether they
+    take card payments — lives here, keyed by LNbits user id, created lazily.
+    The single `chatelet.settings` row keeps only instance-wide knobs; its
+    old house-rule columns stay in place but are no longer read.
+
+    Also indexes bookings by guest so a guest can list their own stays."""
+    await db.execute(f"""
+        CREATE TABLE chatelet.operator_settings (
+            user_id TEXT PRIMARY KEY,
+            accept_fiat BOOLEAN NOT NULL DEFAULT false,
+            checkin_time TEXT NOT NULL DEFAULT '15:00',
+            checkout_time TEXT NOT NULL DEFAULT '11:00',
+            cancellation_policy TEXT NOT NULL DEFAULT '',
+            created_at TIMESTAMP NOT NULL DEFAULT {db.timestamp_now},
+            updated_at TIMESTAMP NOT NULL DEFAULT {db.timestamp_now}
+        );
+        """)
+    await db.execute(
+        "CREATE INDEX chatelet.idx_bookings_guest_pubkey ON bookings (guest_pubkey);"
+    )