feat(mail) : MailMessageReadController + MailMessageFlagController - POST .../read et .../flag

- POST /api/mail/messages/{id}/read body {read: bool} - synchro IMAP + BDD
- POST /api/mail/messages/{id}/flag body {flagged: bool} - synchro IMAP + BDD
- IMAP-side non bloquant : BDD est mise a jour meme si IMAP fail (resync au prochain cycle)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Controller/Mail/MailMessageFlagController.php

@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller\Mail;
+
+use App\Mail\Exception\MailProviderException;
+use App\Mail\MailProviderInterface;
+use App\Repository\MailMessageRepository;
+use App\Security\MailAccessChecker;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Security\Http\Attribute\IsGranted;
+
+#[Route('/api/mail/messages/{id}/flag', name: 'mail_message_flag', methods: ['POST'], priority: 1, requirements: ['id' => '\d+'])]
+#[IsGranted('IS_AUTHENTICATED_FULLY')]
+class MailMessageFlagController extends AbstractController
+{
+    public function __construct(
+        private readonly MailMessageRepository $messageRepository,
+        private readonly MailProviderInterface $mailProvider,
+        private readonly EntityManagerInterface $em,
+        private readonly MailAccessChecker $accessChecker,
+    ) {}
+
+    public function __invoke(Request $request, int $id): JsonResponse
+    {
+        $this->accessChecker->ensureCanAccessMail($this->getUser());
+
+        $message = $this->messageRepository->find($id);
+        if (null === $message) {
+            throw new NotFoundHttpException('Message not found');
+        }
+
+        $body    = json_decode($request->getContent(), true);
+        $flagged = (bool) ($body['flagged'] ?? true);
+
+        try {
+            $this->mailProvider->markFlagged($message->getFolder()->getPath(), $message->getUid(), $flagged);
+        } catch (MailProviderException) {
+            // Non bloquant
+        }
+
+        $message->setIsFlagged($flagged);
+        $this->em->flush();
+
+        return $this->json(['id' => $message->getId(), 'isFlagged' => $message->isFlagged()]);
+    }
+}