The transport form's picker has nine entries, not ten: a transit booking
carries a provider itinerary in metadata.transit and create_transit_journey
is what writes one, so letting a caller hand-make a bare transit row
produces a shape the transit UI does not expect.
Splits the one list in two - what may be asked for, and what counts as a
transport for the update gate - so a stored transit booking stays editable
through update_transport, which is where it was already reachable.
Also reports the ids set_reservation_travelers dropped instead of
returning a plain success with a shorter list.
Maurice
aa5002b2ed