feat: Permettre au super admin de se connecter et accéder à son dashboard

Le super admin (table super_admins, master DB) ne pouvait pas se connecter
via /api/login car ce firewall n'utilisait que le provider tenant. De même,
le JWT n'était pas enrichi pour les super admins, l'endpoint /api/me/roles
les rejetait, et le frontend redirigeait systématiquement vers /dashboard.

Un chain provider (super_admin + tenant) résout l'authentification,
le JwtPayloadEnricher et MyRolesProvider gèrent désormais les deux types
d'utilisateurs, et le frontend redirige selon le rôle après login.

backend/tests/Unit/SuperAdmin/Application/Command/CreateEstablishment/CreateEstablishmentHandlerTest.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\SuperAdmin\Application\Command\CreateEstablishment;
+
+use App\Shared\Domain\Clock;
+use App\SuperAdmin\Application\Command\CreateEstablishment\CreateEstablishmentCommand;
+use App\SuperAdmin\Application\Command\CreateEstablishment\CreateEstablishmentHandler;
+use App\SuperAdmin\Infrastructure\Persistence\InMemory\InMemoryEstablishmentRepository;
+use DateTimeImmutable;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class CreateEstablishmentHandlerTest extends TestCase
+{
+    private const string SUPER_ADMIN_ID = '550e8400-e29b-41d4-a716-446655440001';
+
+    private InMemoryEstablishmentRepository $repository;
+    private CreateEstablishmentHandler $handler;
+
+    protected function setUp(): void
+    {
+        $this->repository = new InMemoryEstablishmentRepository();
+
+        $clock = new class implements Clock {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable('2026-02-16 10:00:00');
+            }
+        };
+
+        $this->handler = new CreateEstablishmentHandler(
+            $this->repository,
+            $clock,
+        );
+    }
+
+    #[Test]
+    public function createsEstablishmentAndReturnsResult(): void
+    {
+        $command = new CreateEstablishmentCommand(
+            name: 'École Alpha',
+            subdomain: 'ecole-alpha',
+            adminEmail: 'admin@ecole-alpha.fr',
+            superAdminId: self::SUPER_ADMIN_ID,
+        );
+
+        $result = ($this->handler)($command);
+
+        self::assertNotEmpty($result->establishmentId);
+        self::assertNotEmpty($result->tenantId);
+        self::assertSame('École Alpha', $result->name);
+        self::assertSame('ecole-alpha', $result->subdomain);
+        self::assertStringStartsWith('classeo_tenant_', $result->databaseName);
+    }
+
+    #[Test]
+    public function savesEstablishmentToRepository(): void
+    {
+        $command = new CreateEstablishmentCommand(
+            name: 'École Beta',
+            subdomain: 'ecole-beta',
+            adminEmail: 'admin@ecole-beta.fr',
+            superAdminId: self::SUPER_ADMIN_ID,
+        );
+
+        $result = ($this->handler)($command);
+
+        $establishments = $this->repository->findAll();
+        self::assertCount(1, $establishments);
+        self::assertSame($result->establishmentId, (string) $establishments[0]->id);
+    }
+}