feat(mail) : MailLinkTask + MailUnlinkTask + TaskMailsList controllers

- POST /api/mail/messages/{id}/link-task body {taskId} : cree TaskMailLink (idempotent)
- DELETE /api/mail/messages/{id}/link-task/{taskId} : supprime le lien (204)
- GET /api/tasks/{id}/mails : liste les mails lies a une tache
- securite via MailAccessChecker, tests fonctionnels 401/403

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

src/Controller/Mail/TaskMailsListController.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller\Mail;
+
+use App\Entity\Task;
+use App\Repository\TaskMailLinkRepository;
+use App\Security\MailAccessChecker;
+use DateTimeInterface;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Security\Http\Attribute\IsGranted;
+
+#[Route('/api/tasks/{id}/mails', name: 'task_mails_list', methods: ['GET'], priority: 1, requirements: ['id' => '\d+'])]
+#[IsGranted('IS_AUTHENTICATED_FULLY')]
+class TaskMailsListController extends AbstractController
+{
+    public function __construct(
+        private readonly EntityManagerInterface $em,
+        private readonly TaskMailLinkRepository $linkRepository,
+        private readonly MailAccessChecker $accessChecker,
+    ) {}
+
+    public function __invoke(int $id): JsonResponse
+    {
+        $this->accessChecker->ensureCanAccessMail($this->getUser());
+
+        $task = $this->em->getRepository(Task::class)->find($id);
+        if (null === $task) {
+            throw new NotFoundHttpException('Task not found');
+        }
+
+        $links = $this->linkRepository->findByTask($task);
+
+        $data = array_map(static fn ($link) => [
+            'id'          => $link->getMailMessage()->getId(),
+            'messageId'   => $link->getMailMessage()->getMessageId(),
+            'subject'     => $link->getMailMessage()->getSubject(),
+            'fromAddress' => $link->getMailMessage()->getFromAddress(),
+            'fromName'    => $link->getMailMessage()->getFromName(),
+            'sentAt'      => $link->getMailMessage()->getSentAt()->format(DateTimeInterface::ATOM),
+            'isRead'      => $link->getMailMessage()->isRead(),
+            'isFlagged'   => $link->getMailMessage()->isFlagged(),
+            'snippet'     => $link->getMailMessage()->getSnippet(),
+            'linkedAt'    => $link->getLinkedAt()->format(DateTimeInterface::ATOM),
+        ], $links);
+
+        return $this->json($data);
+    }
+}