feat(mail) : MailFoldersListController - GET /api/mail/folders (arbre BDD + unreadCount)

- lit la BDD (pas l'IMAP live), retourne l'arbre des dossiers avec metadata
- securite via MailAccessChecker : ROLE_USER/ADMIN, refus ROLE_CLIENT pur
- tests fonctionnels 401/403/200

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

src/Controller/Mail/MailFoldersListController.php

@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller\Mail;
+
+use App\Repository\MailFolderRepository;
+use App\Security\MailAccessChecker;
+use DateTimeInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Security\Http\Attribute\IsGranted;
+
+#[Route('/api/mail/folders', name: 'mail_folders_list', methods: ['GET'], priority: 1)]
+#[IsGranted('IS_AUTHENTICATED_FULLY')]
+class MailFoldersListController extends AbstractController
+{
+    public function __construct(
+        private readonly MailFolderRepository $folderRepository,
+        private readonly MailAccessChecker $accessChecker,
+    ) {}
+
+    public function __invoke(): JsonResponse
+    {
+        $this->accessChecker->ensureCanAccessMail($this->getUser());
+
+        $folders = $this->folderRepository->findAllOrderedByPath();
+
+        $data = array_map(static fn ($folder) => [
+            'id'           => $folder->getId(),
+            'path'         => $folder->getPath(),
+            'displayName'  => $folder->getDisplayName(),
+            'parentPath'   => $folder->getParentPath(),
+            'unreadCount'  => $folder->getUnreadCount(),
+            'totalCount'   => $folder->getTotalCount(),
+            'lastSyncedAt' => $folder->getLastSyncedAt()?->format(DateTimeInterface::ATOM),
+        ], $folders);
+
+        return $this->json($data);
+    }
+}