feat: festival/event model frontend + topbar activeren

- Events lijst: card grid met festival/serie chips
- Festival detail: programmaonderdelen grid
- CreateSubEventDialog voor sub-events binnen festival
- EventTabsNav: breadcrumb terug naar festival
- Sessie A: festival-bewuste EventResource + children endpoint
- Topbar: zoekbalk, theme switcher, shortcuts, notificaties
- Schema v1.7 + BACKLOG.md toegevoegd
- 121 tests groen

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

@@ -14,15 +14,27 @@ final class EventResource extends JsonResource
         return [
             'id' => $this->id,
             'organisation_id' => $this->organisation_id,
+            'parent_event_id' => $this->parent_event_id,
             'name' => $this->name,
             'slug' => $this->slug,
             'start_date' => $this->start_date->toDateString(),
             'end_date' => $this->end_date->toDateString(),
             'timezone' => $this->timezone,
             'status' => $this->status,
+            'event_type' => $this->event_type,
+            'event_type_label' => $this->event_type_label,
+            'sub_event_label' => $this->sub_event_label,
+            'is_recurring' => $this->is_recurring,
+            'is_festival' => $this->resource->isFestival(),
+            'is_sub_event' => $this->resource->isSubEvent(),
+            'is_flat_event' => $this->resource->isFlatEvent(),
+            'has_children' => $this->resource->hasChildren(),
             'created_at' => $this->created_at->toIso8601String(),
             'updated_at' => $this->updated_at->toIso8601String(),
+            'children_count' => $this->whenCounted('children'),
             'organisation' => new OrganisationResource($this->whenLoaded('organisation')),
+            'parent' => new EventResource($this->whenLoaded('parent')),
+            'children' => EventResource::collection($this->whenLoaded('children')),
         ];
     }
 }