feat: fase 2 backend — crowd types, persons, sections, shifts, invite flow

- Crowd Types + Persons CRUD (73 tests)
- Festival Sections + Time Slots + Shifts CRUD met assign/claim flow (84 tests)
- Invite Flow + Member Management met InvitationService (109 tests)
- Schema v1.6 migraties volledig uitgevoerd
- DevSeeder bijgewerkt met crowd types voor testorganisatie

api/app/Http/Resources/Api/V1/TimeSlotResource.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Resources\Api\V1;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+final class TimeSlotResource extends JsonResource
+{
+    public function toArray(Request $request): array
+    {
+        return [
+            'id' => $this->id,
+            'event_id' => $this->event_id,
+            'name' => $this->name,
+            'person_type' => $this->person_type,
+            'date' => $this->date->toDateString(),
+            'start_time' => $this->start_time,
+            'end_time' => $this->end_time,
+            'duration_hours' => $this->duration_hours,
+            'created_at' => $this->created_at->toIso8601String(),
+        ];
+    }
+}