Clients can now request a booking when you have no open times

Some services do not have a fixed schedule — a bespoke consultation, a
by-appointment treatment, or a service a venue is not ready to publish
times for. Clients used to have no way to reach out about these from the
app at all. Now, when a venue turns on booking inquiries for a service, a
client sees an "Inquire" option instead of a dead end. They send their
preferred time, a short note, and their contact details, and the request
lands in the venue's inbox and in a dedicated Booking Inquiries list under
Appointments.

Nothing is booked or charged at this step. A client sends a request, not a
reservation, so there is no confusion about a confirmed time that was never
agreed. When staff have a time that works, one click turns the inquiry into
a real appointment, prefilled with the service, the client's details, and
their preferred time — no retyping across two screens.

This is off by default for every venue. A venue admin turns on booking
inquiries in Appointment settings, then chooses which services accept them
from each service's own page — nothing changes for a venue that has not
opted in, and turning it back off makes the option disappear again without
losing anything already sent.