feat(api): a guest's own bookings on both doors

GET /api/v1/bookings/mine (LNbits account auth; identity = the account's
Nostr pubkey, the same value the booking request carried) and RPC twin
chatelet_booking_list_mine (scoped by the signed sender_pubkey). Rows come
back newest check-in first via the m003 guest index, as guest_booking_dict:
the guest's own contact and counts, minus the Lightning/Nostr plumbing.
Declared ahead of /bookings/{booking_id} so 'mine' is not read as an id.

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

models.py

@@ -259,6 +259,16 @@ def public_booking_dict(booking: "Booking") -> dict:
     return d
 
 
+def guest_booking_dict(booking: "Booking") -> dict:
+    """A Booking for the guest who owns it (authenticated by pubkey on either
+    door): everything public_booking_dict shows plus their own contact and
+    guest count; the Lightning/Nostr plumbing stays internal."""
+    d = json.loads(booking.json())
+    for k in ("payment_hash", "request_event_id", "reservation_event_id"):
+        d.pop(k, None)
+    return d
+
+
 class AvailabilityQuery(BaseModel):
     room_id: str
     check_in: str  # YYYY-MM-DD inclusive