feat(absences) : fondation backend du module de gestion des absences

Module type Payfit (étapes 1+2 de la spec V1) : demande d'absence, validation
admin, soldes à jour.

- Enums : AbsenceType, AbsenceStatus, HalfDay, ContractType, FamilySituation
- Entités : AbsencePolicy, AbsenceBalance, AbsenceRequest + champs RH sur User
- Services : PublicHolidayProvider (fériés FR métropole en PHP pur, Computus),
  AbsenceDayCalculator (décompte jours ouvrés/ouvrables + demi-journées, TDD),
  AbsenceBalanceService (périodes + pending/taken/recrédit)
- API Platform : providers/processors (création, approve/reject/cancel) + RBAC
  me/admin, contrôleurs preview (dry-run), upload/download justificatif, calendrier
- Migrations : une par table + colonnes RH user (DEFAULT puis DROP DEFAULT)
- Fixtures : 5 policies par défaut, salariés démo, soldes et demandes
- Tests unitaires : PublicHolidayProvider, AbsenceDayCalculator (12 tests)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Controller/Absence/AbsenceCalendarController.php

@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller\Absence;
+
+use App\Repository\AbsenceRequestRepository;
+use DateTimeImmutable;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\Exception\UnprocessableEntityHttpException;
+use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Security\Http\Attribute\IsGranted;
+
+/**
+ * Admin calendar view: all pending/approved absences overlapping a date range.
+ */
+class AbsenceCalendarController extends AbstractController
+{
+    public function __construct(
+        private readonly AbsenceRequestRepository $requestRepository,
+    ) {}
+
+    #[Route('/api/admin/absences/calendar', name: 'absence_calendar', methods: ['GET'], priority: 1)]
+    #[IsGranted('ROLE_ADMIN')]
+    public function __invoke(Request $request): JsonResponse
+    {
+        $fromRaw = (string) $request->query->get('from', '');
+        $toRaw   = (string) $request->query->get('to', '');
+
+        if ('' === $fromRaw || '' === $toRaw) {
+            throw new UnprocessableEntityHttpException('Query parameters "from" and "to" are required.');
+        }
+
+        $from = new DateTimeImmutable($fromRaw);
+        $to   = new DateTimeImmutable($toRaw);
+
+        $absences = $this->requestRepository->findInRange($from, $to);
+
+        return $this->json($absences, context: ['groups' => ['absence_request:read']]);
+    }
+}