feat(mail) : MailMessagesListController - GET /api/mail/folders/{path}/messages (pagination cursor)

- MailMessageRepository::findByFolderCursor : pagination cursor sentAt DESC, id DESC
- cursor base64url(sentAt_iso:id), limit max 100
- folderPath URL-encode (requirements: .+ pour supporter les slashes nested)
- securite via MailAccessChecker

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

src/Repository/MailMessageRepository.php

@@ -6,6 +6,8 @@ namespace App\Repository;
 
 use App\Entity\MailFolder;
 use App\Entity\MailMessage;
+use DateTimeImmutable;
+use DateTimeInterface;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
 use Doctrine\Persistence\ManagerRegistry;
 
@@ -99,4 +101,52 @@ class MailMessageRepository extends ServiceEntityRepository
 
         return array_column($rows, 'uid');
     }
+
+    /**
+     * Pagination cursor : retourne $limit messages apres le cursor (sentAt DESC, id DESC).
+     * Cursor format : base64url(sentAt_iso8601:id) - null pour la premiere page.
+     *
+     * @return array{messages: list<MailMessage>, nextCursor: ?string}
+     */
+    public function findByFolderCursor(MailFolder $folder, int $limit, ?string $cursor): array
+    {
+        $qb = $this->createQueryBuilder('m')
+            ->andWhere('m.folder = :folder')
+            ->setParameter('folder', $folder)
+            ->orderBy('m.sentAt', 'DESC')
+            ->addOrderBy('m.id', 'DESC')
+            ->setMaxResults($limit + 1)
+        ;
+
+        if (null !== $cursor) {
+            $decoded = base64_decode(strtr($cursor, '-_', '+/'), true);
+            if (false !== $decoded && str_contains($decoded, ':')) {
+                [$sentAtStr, $idStr] = explode(':', $decoded, 2);
+                $cursorSentAt        = DateTimeImmutable::createFromFormat(DateTimeInterface::ATOM, $sentAtStr);
+                $cursorId            = (int) $idStr;
+
+                if ($cursorSentAt instanceof DateTimeImmutable) {
+                    $qb
+                        ->andWhere('m.sentAt < :cursorSentAt OR (m.sentAt = :cursorSentAt AND m.id < :cursorId)')
+                        ->setParameter('cursorSentAt', $cursorSentAt)
+                        ->setParameter('cursorId', $cursorId)
+                    ;
+                }
+            }
+        }
+
+        /** @var list<MailMessage> $results */
+        $results    = $qb->getQuery()->getResult();
+        $hasMore    = count($results) > $limit;
+        $messages   = $hasMore ? array_slice($results, 0, $limit) : $results;
+        $nextCursor = null;
+
+        if ($hasMore && [] !== $messages) {
+            $last       = end($messages);
+            $raw        = $last->getSentAt()->format(DateTimeInterface::ATOM).':'.$last->getId();
+            $nextCursor = rtrim(strtr(base64_encode($raw), '+/', '-_'), '=');
+        }
+
+        return ['messages' => $messages, 'nextCursor' => $nextCursor];
+    }
 }