feat(appointment): log cancellation events and show them in a Timeline

Introduce the first per-appointment event system. On cancel (via the status
or general update endpoints) an AppointmentEvent (type=cancelled, «نوبت لغو
شد») is recorded with the actor, cancel time, and an optional cancel_reason,
plus a warning-level app_log entry. New GET /appointment/{uuid}/events
returns the ordered event list. The admin appointment detail page renders a
Timeline section and the cancel dialog now collects an optional reason.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

migrations/Version20260717073617.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20260717073617 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add appointment_events table (appointment Timeline / audit events)';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('CREATE TABLE appointment_events (id INT AUTO_INCREMENT NOT NULL, uuid VARCHAR(36) NOT NULL, type VARCHAR(40) NOT NULL, title VARCHAR(191) NOT NULL, actor_user_id INT DEFAULT NULL, actor_name VARCHAR(191) DEFAULT NULL, reason LONGTEXT DEFAULT NULL, created_at INT NOT NULL, appointment_id INT NOT NULL, UNIQUE INDEX UNIQ_14D9E804D17F50A6 (uuid), INDEX IDX_14D9E804E5B533F9 (appointment_id), INDEX idx_appointment_events_appt (appointment_id, created_at), PRIMARY KEY (id)) DEFAULT CHARACTER SET utf8mb4');
+        $this->addSql('ALTER TABLE appointment_events ADD CONSTRAINT FK_14D9E804E5B533F9 FOREIGN KEY (appointment_id) REFERENCES appointments (id) ON DELETE CASCADE');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE appointment_events DROP FOREIGN KEY FK_14D9E804E5B533F9');
+        $this->addSql('DROP TABLE appointment_events');
+    }
+}