feat(mail) : migrate Mail integration into module (back)

LST-67 (2.5) backend. Behaviour-preserving move of the IMAP mail integration
into src/Module/Mail/. All /api/mail/* routes, securities (ROLE_CLIENT still
excluded via MailAccessChecker) and the async sync are unchanged.

- 4 entities + 4 repositories (Domain interfaces + Doctrine impls, bound).
  TaskMailLink.task now references TaskInterface (contract) instead of the
  concrete PM Task. Link/unlink/list-mails controllers load tasks via
  TaskRepositoryInterface; MailCreateTaskController keeps the concrete Task
  (instantiation) — documented Mail->PM coupling.
- Domain (MailProviderInterface, exception), Application (5 DTOs, MailSyncService,
  MailSyncRequested message + handler), Infrastructure (ImapMailProvider +
  MimeHeaderDecoder, MailAccessChecker, 2 console commands, 12 controllers,
  ApiPlatform state + MailSettings resource). TokenEncryptor stays shared.
- doctrine mapping Mail; messenger routing repointed; services.yaml repo +
  provider bindings; MailModule registered (id mail, mail.access/configure).
- #[Auditable] + Timestampable on MailConfiguration only (additive migration);
  IMAP data entities keep their own sync timestamps.

163 tests green, mapping valid, no route regression, cs-fixer clean.

tests/Unit/Mail/ImapMailProviderTest.php

@@ -4,10 +4,10 @@ declare(strict_types=1);
 
 namespace App\Tests\Unit\Mail;
 
-use App\Entity\MailConfiguration;
-use App\Mail\Exception\MailProviderException;
-use App\Mail\ImapMailProvider;
-use App\Repository\MailConfigurationRepository;
+use App\Module\Mail\Domain\Entity\MailConfiguration;
+use App\Module\Mail\Domain\Exception\MailProviderException;
+use App\Module\Mail\Domain\Repository\MailConfigurationRepositoryInterface;
+use App\Module\Mail\Infrastructure\Imap\ImapMailProvider;
 use App\Service\TokenEncryptor;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\NullLogger;
@@ -22,7 +22,7 @@ class ImapMailProviderTest extends TestCase
         $config = new MailConfiguration();
         $config->setEnabled(false);
 
-        $repo = $this->createMock(MailConfigurationRepository::class);
+        $repo = $this->createMock(MailConfigurationRepositoryInterface::class);
         $repo->method('findSingleton')->willReturn($config);
 
         $provider = new ImapMailProvider($repo, $this->makeEncryptor(), new NullLogger());
@@ -33,7 +33,7 @@ class ImapMailProviderTest extends TestCase
 
     public function testThrowsWhenConfigMissing(): void
     {
-        $repo = $this->createMock(MailConfigurationRepository::class);
+        $repo = $this->createMock(MailConfigurationRepositoryInterface::class);
         $repo->method('findSingleton')->willReturn(null);
 
         $provider = new ImapMailProvider($repo, $this->makeEncryptor(), new NullLogger());

tests/Unit/Mail/MailSyncReportTest.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace App\Tests\Unit\Mail;
 
-use App\Mail\Dto\MailSyncReport;
+use App\Module\Mail\Application\Dto\MailSyncReport;
 use DateTimeImmutable;
 use PHPUnit\Framework\TestCase;
 

tests/Unit/Mail/MimeHeaderDecoderTest.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace App\Tests\Unit\Mail;
 
-use App\Mail\MimeHeaderDecoder;
+use App\Module\Mail\Infrastructure\Imap\MimeHeaderDecoder;
 use PHPUnit\Framework\TestCase;
 
 /**