feat: add service-based booking mode to appointment scheduling

- Introduced a new booking mode in WeeklySchedule to support service-based appointments.
- Updated SlotCalculatorService to calculate available start times based on selected service durations and buffer times.
- Enhanced AppointmentController to handle service items during booking, calculating slot_end on the server side.
- Implemented validation to ensure at least one bookable service exists for doctors in service mode.
- Added new API endpoint to retrieve available appointment slots based on selected services.
- Updated MyAppointmentsController to accept service items during appointment creation.
- Modified ServiceItem entity to include a bookable flag, allowing services to be marked for scheduling.
- Created migration to add bookable column to service_items table.
- Added tests for service-based slot calculations and validation logic.

src/Appointment/Repository/AppointmentRepository.php

@@ -7,6 +7,7 @@ use App\Auth\Entity\User;
 use App\Doctor\Entity\Doctor;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
 use Doctrine\DBAL\Exception\UniqueConstraintViolationException;
+use Doctrine\DBAL\LockMode;
 use Doctrine\ORM\OptimisticLockException;
 use Doctrine\Persistence\ManagerRegistry;
 
@@ -37,6 +38,13 @@ class AppointmentRepository extends ServiceEntityRepository
                 $start  = $appointment->getSlotStart();
                 $end    = $appointment->getSlotEnd();
 
+                // قفلِ per-doctor (SELECT ... FOR UPDATE روی ردیف پزشک): رزروهای
+                // هم‌زمانِ یک پزشک را سریالایز می‌کند. در حالت نوبت‌دهی سرویسی که
+                // نوبت‌ها طول متغیر و شروعِ متفاوت دارند، unique-keyِ (doctor,slot_start)
+                // تداخلِ بازه‌ایِ دو رزروِ هم‌زمان را نمی‌گیرد؛ این قفل تضمین می‌کند
+                // بررسیِ isSlotTaken و insert به‌صورت اتمیک نسبت به سایر رزروها انجام شود.
+                $em->lock($doctor, LockMode::PESSIMISTIC_WRITE);
+
                 if ($this->isSlotTaken($doctor, $start, $end)) {
                     throw new SlotTakenException();
                 }
@@ -87,6 +95,37 @@ class AppointmentRepository extends ServiceEntityRepository
         $this->getEntityManager()->flush();
     }
 
+    /**
+     * بازه‌های اشغال‌شدهٔ یک پزشک در پنجرهٔ [$from, $to) — برای محاسبهٔ زمانِ خالی
+     * در حالت نوبت‌دهی سرویسی. همان معیارِ isSlotTaken (blocking یا pendingِ زنده)،
+     * ولی نوبت‌های «آزاد» (is_reserve) هیچ بازه‌ای اشغال نمی‌کنند.
+     *
+     * @return array<array{start:int,end:int}> مرتب‌شده بر اساس start
+     */
+    public function findBusyIntervals(Doctor $doctor, int $from, int $to): array
+    {
+        $rows = $this->createQueryBuilder('a')
+            ->select('a.slotStart AS start, a.slotEnd AS end')
+            ->where('a.doctor = :doctor')
+            ->andWhere('a.isReserve = false')
+            ->andWhere('a.slotStart < :to')
+            ->andWhere('a.slotEnd > :from')
+            ->andWhere(
+                'a.status IN (:blocking) OR (a.status = :pending AND (a.expiresAt IS NULL OR a.expiresAt > :now))'
+            )
+            ->setParameter('doctor', $doctor)
+            ->setParameter('blocking', Appointment::SLOT_BLOCKING_STATUSES)
+            ->setParameter('pending', Appointment::STATUS_PENDING)
+            ->setParameter('now', time())
+            ->setParameter('from', $from)
+            ->setParameter('to', $to)
+            ->orderBy('a.slotStart', 'ASC')
+            ->getQuery()
+            ->getScalarResult();
+
+        return array_map(fn($r) => ['start' => (int) $r['start'], 'end' => (int) $r['end']], $rows);
+    }
+
     /** Check if a slot is already taken (confirmed or pending) */
     public function isSlotTaken(Doctor $doctor, int $slotStart, int $slotEnd, ?int $excludeId = null): bool
     {