feat(appointment): expire pending bookings past their payment window

Add findPaymentExpired (pending with expires_at < now) and have the
cancel-expired command flip both payment-expired and slot-time-passed
pendings to expired (deduped). Run it on a schedule (e.g. every minute:
* * * * * php bin/console app:cancel-expired-appointments) to free locks
held by unpaid bookings.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Appointment/Repository/AppointmentRepository.php

@@ -80,6 +80,19 @@ class AppointmentRepository extends ServiceEntityRepository
         return $this->findBy($criteria, ['slotStart' => 'DESC']);
     }
 
+    /** @return Appointment[] pending bookings whose 15-minute payment window has lapsed */
+    public function findPaymentExpired(int $now): array
+    {
+        return $this->createQueryBuilder('a')
+            ->where('a.status = :status')
+            ->andWhere('a.expiresAt IS NOT NULL')
+            ->andWhere('a.expiresAt < :now')
+            ->setParameter('status', Appointment::STATUS_PENDING)
+            ->setParameter('now', $now)
+            ->getQuery()
+            ->getResult();
+    }
+
     /** @return Appointment[] pending appointments older than given timestamp */
     public function findExpiredPending(int $before): array
     {