findBusyIntervals() and getServiceStartTimes() gain an optional
excludeAppointmentId, mirroring isSlotTaken($doctor, $start, $end, $excludeId)
which already had it. Without it an appointment being rescheduled sees itself as
busy, so its current time never appears among the candidates and "same hour,
different service" is impossible.
The parameter is optional with a null default and only affects the service-mode
path; no existing call site changes behaviour. SlotModeFrozenTest caught the
signature change immediately while both response contracts stayed green, so the
signature fixture was updated once with a written rationale, as its own header
permits.
Task: docs/new_feture/taskes/task-00-service-mode-completion/
Slot-mode contract: unchanged (--group=slot-mode-frozen green)
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
