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/src/Scolarite/Application/Query/GetClassStatisticsDetail/ClassStatisticsDetailDto.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetClassStatisticsDetail;
+
+final readonly class ClassStatisticsDetailDto
+{
+    /**
+     * @param list<int>                                  $distribution
+     * @param list<array{month: string, average: float}> $evolution
+     * @param list<StudentAverageDto>                    $students
+     */
+    public function __construct(
+        public ?float $average,
+        public float $successRate,
+        public array $distribution,
+        public array $evolution,
+        public array $students,
+    ) {
+    }
+}

backend/src/Scolarite/Application/Query/GetClassStatisticsDetail/GetClassStatisticsDetailHandler.php

@@ -0,0 +1,113 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetClassStatisticsDetail;
+
+use App\Scolarite\Application\Port\PeriodFinder;
+use App\Scolarite\Application\Port\TeacherStatisticsReader;
+use App\Scolarite\Domain\Service\AverageCalculator;
+use App\Scolarite\Domain\Service\TeacherStatisticsCalculator;
+use App\Shared\Domain\Tenant\TenantId;
+
+use function array_map;
+use function count;
+
+use DateTimeImmutable;
+
+use function sprintf;
+
+use Symfony\Component\Messenger\Attribute\AsMessageHandler;
+
+#[AsMessageHandler(bus: 'query.bus')]
+final readonly class GetClassStatisticsDetailHandler
+{
+    public function __construct(
+        private TeacherStatisticsReader $reader,
+        private PeriodFinder $periodFinder,
+        private TeacherStatisticsCalculator $statisticsCalculator,
+        private AverageCalculator $averageCalculator,
+    ) {
+    }
+
+    public function __invoke(GetClassStatisticsDetailQuery $query): ClassStatisticsDetailDto
+    {
+        $tenantId = TenantId::fromString($query->tenantId);
+        $period = $this->periodFinder->findForDate(new DateTimeImmutable(), $tenantId);
+
+        if ($period === null) {
+            return new ClassStatisticsDetailDto(
+                average: null,
+                successRate: 0.0,
+                distribution: [0, 0, 0, 0, 0, 0, 0, 0],
+                evolution: [],
+                students: [],
+            );
+        }
+
+        $normalizedGrades = $this->reader->classGradesNormalized(
+            $query->teacherId,
+            $query->classId,
+            $query->subjectId,
+            $query->tenantId,
+            $period->startDate->format('Y-m-d'),
+            $period->endDate->format('Y-m-d'),
+        );
+
+        $classStats = $this->averageCalculator->calculateClassStatistics($normalizedGrades);
+        $distribution = $this->statisticsCalculator->calculateDistribution($normalizedGrades);
+        $successRate = $this->statisticsCalculator->calculateSuccessRate($normalizedGrades);
+
+        $now = new DateTimeImmutable();
+        $month = (int) $now->format('n');
+        $yearStart = $month >= 9 ? (int) $now->format('Y') : (int) $now->format('Y') - 1;
+        $academicYearStart = sprintf('%d-09-01', $yearStart);
+        $academicYearEnd = sprintf('%d-08-31', $yearStart + 1);
+
+        $evolution = $this->reader->classMonthlyAverages(
+            $query->teacherId,
+            $query->classId,
+            $query->subjectId,
+            $query->tenantId,
+            $academicYearStart,
+            $academicYearEnd,
+        );
+
+        $studentAverages = $this->reader->studentAveragesForClass(
+            $query->teacherId,
+            $query->classId,
+            $query->subjectId,
+            $period->periodId,
+            $query->tenantId,
+        );
+
+        $studentTrends = $this->reader->studentMonthlyAveragesForClass(
+            $query->classId,
+            $query->subjectId,
+            $query->tenantId,
+            $academicYearStart,
+            $academicYearEnd,
+        );
+
+        $students = array_map(
+            fn (array $s) => new StudentAverageDto(
+                studentId: $s['studentId'],
+                studentName: $s['studentName'],
+                average: $s['average'],
+                inDifficulty: $s['average'] !== null && $s['average'] < $query->threshold,
+                trend: isset($studentTrends[$s['studentId']]) && count($studentTrends[$s['studentId']]) >= 2
+                    ? $this->statisticsCalculator->detectTrend($studentTrends[$s['studentId']])
+                    : 'stable',
+            ),
+            $studentAverages,
+        );
+
+        return new ClassStatisticsDetailDto(
+            average: $classStats->average,
+            successRate: $successRate,
+            distribution: $distribution,
+            evolution: $evolution,
+            students: $students,
+        );
+    }
+}

backend/src/Scolarite/Application/Query/GetClassStatisticsDetail/GetClassStatisticsDetailQuery.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetClassStatisticsDetail;
+
+final readonly class GetClassStatisticsDetailQuery
+{
+    public function __construct(
+        public string $teacherId,
+        public string $classId,
+        public string $subjectId,
+        public string $tenantId,
+        public float $threshold = 8.0,
+    ) {
+    }
+}

backend/src/Scolarite/Application/Query/GetClassStatisticsDetail/StudentAverageDto.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Scolarite\Application\Query\GetClassStatisticsDetail;
+
+final readonly class StudentAverageDto
+{
+    public function __construct(
+        public string $studentId,
+        public string $studentName,
+        public ?float $average,
+        public bool $inDifficulty,
+        public string $trend,
+    ) {
+    }
+}