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/InvitationResource.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Resources\Api\V1;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+final class InvitationResource extends JsonResource
+{
+    public function toArray(Request $request): array
+    {
+        return [
+            'id' => $this->id,
+            'email' => $this->email,
+            'role' => $this->role,
+            'status' => $this->isExpired() && $this->isPending() ? 'expired' : $this->status,
+            'expires_at' => $this->expires_at->toIso8601String(),
+            'created_at' => $this->created_at->toIso8601String(),
+            'organisation' => $this->whenLoaded('organisation', fn () => [
+                'name' => $this->organisation->name,
+            ]),
+            'invited_by' => $this->whenLoaded('invitedBy', fn () => [
+                'name' => $this->invitedBy?->name,
+            ]),
+        ];
+    }
+}