The backend already accepted staff_uuid on POST /api/v1/my/appointment; only
the booking modal never sent it, so the pre-assignment half of the operator
model had no way in.
The field sits in step 1 next to the section select and is optional by design:
left empty, the session stays in the shared queue that every allowed operator
sees. Its placeholder says so rather than leaving the blank state unexplained.
The section select is no longer the only combobox in the modal, so the tests
target it by its label instead of by role.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
