feat(booking): let service slot search exclude the appointment being moved

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>

src/Appointment/Service/SlotCalculatorService.php

@@ -100,9 +100,13 @@ class SlotCalculatorService
      * زمان پایانِ ذخیره‌شدهٔ نوبت = start + duration (بدون بافر)؛ بافر فقط فاصلهٔ
      * بین دو نوبت است، پس candidate بعدی از start + duration + buffer شروع می‌شود.
      *
+     * `$excludeAppointmentId` برای جابه‌جایی خودِ یک نوبت است: بدون آن، نوبتِ در حال
+     * جابه‌جایی خودش را اشغال می‌بیند و زمان فعلی‌اش در فهرست نمی‌آید. همان الگوی
+     * {@see \App\Appointment\Repository\AppointmentRepository::isSlotTaken()}.
+     *
      * @return array<array{start:int,end:int,start_time:string,end_time:string,location_id:?int}>
      */
-    public function getServiceStartTimes(Doctor $doctor, string $date, int $durationMinutes, ?Clinic $clinic = null, bool $forManagement = false): array
+    public function getServiceStartTimes(Doctor $doctor, string $date, int $durationMinutes, ?Clinic $clinic = null, bool $forManagement = false, ?int $excludeAppointmentId = null): array
     {
         if ($durationMinutes <= 0) return [];
 
@@ -114,7 +118,7 @@ class SlotCalculatorService
         if (empty($sessions)) return [];
 
         $dayStart = (int) strtotime($date . ' 00:00:00');
-        $busy     = $this->appointmentRepo->findBusyIntervals($doctor, $dayStart, $dayStart + 86400);
+        $busy     = $this->appointmentRepo->findBusyIntervals($doctor, $dayStart, $dayStart + 86400, $excludeAppointmentId);
         $now      = time();
 
         $result = [];