feat(appointment): auto-expire unpaid bookings via Symfony Scheduler

Run the 15-min payment-expiry every minute through Symfony Scheduler so
unpaid pending bookings flip to expired without a system crontab. Install
symfony/scheduler; extract the expiry logic into AppointmentExpiryService
(reused by the existing command); add ExpireAppointmentsMessage + handler
and an #[AsSchedule] provider (RecurringMessage::every 1 minute); wire a
scheduler_default transport in messenger.yaml. Slots already free
just-in-time via isSlotTaken, so this only syncs the DB status.

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

src/Appointment/Service/AppointmentExpiryService.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Appointment\Service;
+
+use App\Appointment\Entity\Appointment;
+use App\Appointment\Repository\AppointmentRepository;
+
+class AppointmentExpiryService
+{
+    public function __construct(private readonly AppointmentRepository $appointmentRepo) {}
+
+    /**
+     * Expire pending bookings whose payment window has lapsed or whose slot
+     * time has already passed. Idempotent — safe to run repeatedly.
+     *
+     * @return int number of appointments expired
+     */
+    public function expireStale(): int
+    {
+        $now = time();
+
+        $expired = [];
+        foreach ([...$this->appointmentRepo->findPaymentExpired($now), ...$this->appointmentRepo->findExpiredPending($now)] as $appointment) {
+            $expired[$appointment->getUuid()] = $appointment;
+        }
+
+        $count = 0;
+        foreach ($expired as $appointment) {
+            $appointment->transitionTo(Appointment::STATUS_EXPIRED);
+            $this->appointmentRepo->save($appointment, false);
+            $count++;
+        }
+
+        if ($count > 0) {
+            $this->appointmentRepo->save(reset($expired)); // flush once
+        }
+
+        return $count;
+    }
+}