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/GetClassStatisticsDetail/GetClassStatisticsDetailHandlerTest.php

@@ -0,0 +1,109 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Application\Query\GetClassStatisticsDetail;
+
+use App\Scolarite\Application\Port\PeriodFinder;
+use App\Scolarite\Application\Port\PeriodInfo;
+use App\Scolarite\Application\Query\GetClassStatisticsDetail\GetClassStatisticsDetailHandler;
+use App\Scolarite\Application\Query\GetClassStatisticsDetail\GetClassStatisticsDetailQuery;
+use App\Scolarite\Domain\Service\AverageCalculator;
+use App\Scolarite\Domain\Service\TeacherStatisticsCalculator;
+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 GetClassStatisticsDetailHandlerTest extends TestCase
+{
+    private const string TEACHER_ID = '550e8400-e29b-41d4-a716-446655440010';
+    private const string TENANT_ID = '550e8400-e29b-41d4-a716-446655440001';
+    private const string CLASS_ID = '550e8400-e29b-41d4-a716-446655440020';
+    private const string SUBJECT_ID = '550e8400-e29b-41d4-a716-446655440030';
+
+    private InMemoryTeacherStatisticsReader $reader;
+
+    protected function setUp(): void
+    {
+        $this->reader = new InMemoryTeacherStatisticsReader();
+    }
+
+    #[Test]
+    public function itReturnsEmptyWhenNoPeriodFound(): void
+    {
+        $handler = $this->createHandler(periodInfo: null);
+
+        $result = $handler($this->query());
+
+        self::assertNull($result->average);
+        self::assertSame(0.0, $result->successRate);
+        self::assertSame([], $result->students);
+    }
+
+    #[Test]
+    public function itComputesClassStatisticsFromGrades(): void
+    {
+        $this->reader->feedClassGrades([8.0, 10.0, 12.0, 14.0, 16.0]);
+        $this->reader->feedMonthlyAverages([
+            ['month' => '2026-01', 'average' => 11.0],
+            ['month' => '2026-02', 'average' => 12.5],
+        ]);
+        $this->reader->feedStudentAverages([
+            ['studentId' => 's1', 'studentName' => 'Alice Dupont', 'average' => 14.0],
+            ['studentId' => 's2', 'studentName' => 'Bob Martin', 'average' => 7.0],
+        ]);
+
+        $handler = $this->createHandler(periodInfo: $this->currentPeriod());
+        $result = $handler($this->query());
+
+        self::assertSame(12.0, $result->average);
+        self::assertSame(80.0, $result->successRate); // 4/5 >= 10
+        self::assertSame([0, 0, 0, 1, 2, 1, 1, 0], $result->distribution);
+        self::assertCount(2, $result->evolution);
+        self::assertCount(2, $result->students);
+        self::assertFalse($result->students[0]->inDifficulty); // Alice 14.0 >= 8.0
+        self::assertTrue($result->students[1]->inDifficulty); // Bob 7.0 < 8.0
+    }
+
+    private function query(): GetClassStatisticsDetailQuery
+    {
+        return new GetClassStatisticsDetailQuery(
+            teacherId: self::TEACHER_ID,
+            classId: self::CLASS_ID,
+            subjectId: self::SUBJECT_ID,
+            tenantId: self::TENANT_ID,
+        );
+    }
+
+    private function createHandler(?PeriodInfo $periodInfo): GetClassStatisticsDetailHandler
+    {
+        $periodFinder = new class($periodInfo) implements PeriodFinder {
+            public function __construct(private readonly ?PeriodInfo $info)
+            {
+            }
+
+            public function findForDate(DateTimeImmutable $date, TenantId $tenantId): ?PeriodInfo
+            {
+                return $this->info;
+            }
+        };
+
+        return new GetClassStatisticsDetailHandler(
+            $this->reader,
+            $periodFinder,
+            new TeacherStatisticsCalculator(),
+            new AverageCalculator(),
+        );
+    }
+
+    private function currentPeriod(): PeriodInfo
+    {
+        return new PeriodInfo(
+            periodId: 'period-1',
+            startDate: new DateTimeImmutable('2026-01-05'),
+            endDate: new DateTimeImmutable('2026-03-31'),
+        );
+    }
+}