feat: Provisionner automatiquement un nouvel établissement

Lorsqu'un super-admin crée un établissement via l'interface, le système
doit automatiquement créer la base tenant, exécuter les migrations,
créer le premier utilisateur admin et envoyer l'invitation — le tout
de manière asynchrone pour ne pas bloquer la réponse HTTP.

Ce mécanisme rend chaque établissement opérationnel dès sa création
sans intervention manuelle sur l'infrastructure.

backend/tests/Unit/Scolarite/Application/Query/GetTeacherStatisticsOverview/GetTeacherStatisticsOverviewHandlerTest.php

@@ -0,0 +1,106 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Application\Query\GetTeacherStatisticsOverview;
+
+use App\Scolarite\Application\Port\PeriodFinder;
+use App\Scolarite\Application\Port\PeriodInfo;
+use App\Scolarite\Application\Query\GetTeacherStatisticsOverview\GetTeacherStatisticsOverviewHandler;
+use App\Scolarite\Application\Query\GetTeacherStatisticsOverview\GetTeacherStatisticsOverviewQuery;
+use App\Scolarite\Infrastructure\ReadModel\InMemoryTeacherStatisticsReader;
+use App\Shared\Domain\Tenant\TenantId;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class GetTeacherStatisticsOverviewHandlerTest extends TestCase
+{
+    private const string TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+
+    private InMemoryTeacherStatisticsReader $reader;
+
+    protected function setUp(): void
+    {
+        $this->reader = new InMemoryTeacherStatisticsReader();
+    }
+
+    #[Test]
+    public function itReturnsEmptyWhenNoPeriodFound(): void
+    {
+        $handler = $this->createHandler(periodInfo: null);
+
+        $result = $handler(new GetTeacherStatisticsOverviewQuery(
+            teacherId: self::TEACHER_ID,
+            tenantId: self::TENANT_ID,
+        ));
+
+        self::assertSame([], $result);
+    }
+
+    #[Test]
+    public function itReturnsClassOverviewDtos(): void
+    {
+        $this->reader->feedClassesSummary([
+            [
+                'classId' => 'class-1',
+                'className' => '6ème A',
+                'subjectId' => 'subject-1',
+                'subjectName' => 'Mathématiques',
+                'evaluationCount' => 3,
+                'studentCount' => 25,
+                'average' => 12.5,
+                'successRate' => 72.0,
+            ],
+            [
+                'classId' => 'class-2',
+                'className' => '5ème B',
+                'subjectId' => 'subject-1',
+                'subjectName' => 'Mathématiques',
+                'evaluationCount' => 2,
+                'studentCount' => 28,
+                'average' => 10.8,
+                'successRate' => 57.0,
+            ],
+        ]);
+
+        $handler = $this->createHandler(periodInfo: $this->currentPeriod());
+
+        $result = $handler(new GetTeacherStatisticsOverviewQuery(
+            teacherId: self::TEACHER_ID,
+            tenantId: self::TENANT_ID,
+        ));
+
+        self::assertCount(2, $result);
+        self::assertSame('6ème A', $result[0]->className);
+        self::assertSame(12.5, $result[0]->average);
+        self::assertSame(72.0, $result[0]->successRate);
+        self::assertSame('5ème B', $result[1]->className);
+    }
+
+    private function createHandler(?PeriodInfo $periodInfo): GetTeacherStatisticsOverviewHandler
+    {
+        $periodFinder = new class($periodInfo) implements PeriodFinder {
+            public function __construct(private readonly ?PeriodInfo $info)
+            {
+            }
+
+            public function findForDate(DateTimeImmutable $date, TenantId $tenantId): ?PeriodInfo
+            {
+                return $this->info;
+            }
+        };
+
+        return new GetTeacherStatisticsOverviewHandler($this->reader, $periodFinder);
+    }
+
+    private function currentPeriod(): PeriodInfo
+    {
+        return new PeriodInfo(
+            periodId: 'period-1',
+            startDate: new DateTimeImmutable('2026-01-05'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+        );
+    }
+}