feat: Gestion des classes scolaires

Permet aux administrateurs de créer, modifier et supprimer des classes
pour organiser les élèves par niveau. L'archivage soft-delete préserve
l'historique tout en masquant les classes obsolètes.

Inclut la validation des noms (2-50 caractères), les niveaux scolaires
du CP à la Terminale, et les contrôles d'accès par rôle.

backend/tests/Unit/Administration/Application/Command/ArchiveClass/ArchiveClassHandlerTest.php

@@ -0,0 +1,135 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Administration\Application\Command\ArchiveClass;
+
+use App\Administration\Application\Command\ArchiveClass\ArchiveClassCommand;
+use App\Administration\Application\Command\ArchiveClass\ArchiveClassHandler;
+use App\Administration\Application\Query\HasStudentsInClass\HasStudentsInClassQuery;
+use App\Administration\Domain\Exception\ClasseNonSupprimableException;
+use App\Administration\Domain\Model\SchoolClass\AcademicYearId;
+use App\Administration\Domain\Model\SchoolClass\ClassName;
+use App\Administration\Domain\Model\SchoolClass\ClassStatus;
+use App\Administration\Domain\Model\SchoolClass\SchoolClass;
+use App\Administration\Domain\Model\SchoolClass\SchoolId;
+use App\Administration\Domain\Model\SchoolClass\SchoolLevel;
+use App\Administration\Infrastructure\Persistence\InMemory\InMemoryClassRepository;
+use App\Shared\Domain\Clock;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use RuntimeException;
+use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Messenger\Stamp\HandledStamp;
+
+final class ArchiveClassHandlerTest extends TestCase
+{
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string SCHOOL_ID = '550e8400-e29b-41d4-a716-446655440002';
+    private const string ACADEMIC_YEAR_ID = '550e8400-e29b-41d4-a716-446655440003';
+
+    private InMemoryClassRepository $classRepository;
+    private Clock $clock;
+
+    protected function setUp(): void
+    {
+        $this->classRepository = new InMemoryClassRepository();
+        $this->clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-02-01 10:00:00');
+            }
+        };
+    }
+
+    #[Test]
+    public function itArchivesEmptyClass(): void
+    {
+        $class = $this->createAndSaveClass();
+        $queryBus = $this->createQueryBusReturning(0);
+        $handler = new ArchiveClassHandler($this->classRepository, $queryBus, $this->clock);
+
+        $command = new ArchiveClassCommand(classId: (string) $class->id);
+
+        $handler($command);
+
+        $archivedClass = $this->classRepository->get($class->id);
+        self::assertSame(ClassStatus::ARCHIVED, $archivedClass->status);
+        self::assertNotNull($archivedClass->deletedAt);
+    }
+
+    #[Test]
+    public function itThrowsExceptionWhenStudentsAreAffected(): void
+    {
+        $class = $this->createAndSaveClass();
+        $queryBus = $this->createQueryBusReturning(5);
+        $handler = new ArchiveClassHandler($this->classRepository, $queryBus, $this->clock);
+
+        $command = new ArchiveClassCommand(classId: (string) $class->id);
+
+        $this->expectException(ClasseNonSupprimableException::class);
+        $this->expectExceptionMessage('5 élève(s)');
+
+        $handler($command);
+    }
+
+    #[Test]
+    public function itDoesNotModifyStatusWhenAlreadyArchived(): void
+    {
+        $class = $this->createAndSaveClass();
+        $archiveTime = new DateTimeImmutable('2026-01-20 10:00:00');
+        $class->archiver($archiveTime);
+        $this->classRepository->save($class);
+
+        $queryBus = $this->createQueryBusReturning(0);
+        $handler = new ArchiveClassHandler($this->classRepository, $queryBus, $this->clock);
+
+        $command = new ArchiveClassCommand(classId: (string) $class->id);
+
+        $handler($command);
+
+        $archivedClass = $this->classRepository->get($class->id);
+        // deletedAt should not have changed
+        self::assertEquals($archiveTime, $archivedClass->deletedAt);
+    }
+
+    private function createAndSaveClass(): SchoolClass
+    {
+        $class = SchoolClass::creer(
+            tenantId: TenantId::fromString(self::TENANT_ID),
+            schoolId: SchoolId::fromString(self::SCHOOL_ID),
+            academicYearId: AcademicYearId::fromString(self::ACADEMIC_YEAR_ID),
+            name: new ClassName('6ème A'),
+            level: SchoolLevel::SIXIEME,
+            capacity: 30,
+            createdAt: new DateTimeImmutable('2026-01-15 10:00:00'),
+        );
+
+        $this->classRepository->save($class);
+
+        return $class;
+    }
+
+    private function createQueryBusReturning(int $studentCount): MessageBusInterface
+    {
+        return new class($studentCount) implements MessageBusInterface {
+            public function __construct(private readonly int $studentCount)
+            {
+            }
+
+            public function dispatch(object $message, array $stamps = []): Envelope
+            {
+                if (!$message instanceof HasStudentsInClassQuery) {
+                    throw new RuntimeException('Unexpected message type');
+                }
+
+                $envelope = new Envelope($message);
+
+                return $envelope->with(new HandledStamp($this->studentCount, 'handler'));
+            }
+        };
+    }
+}