feat: festival/series model with sub-events, cross-event sections, tab navigation, SectionsShiftsPanel extraction

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/app/Http/Controllers/Api/V1/FestivalSectionController.php

@@ -23,6 +23,17 @@ final class FestivalSectionController extends Controller
 
         $sections = $event->festivalSections()->ordered()->get();
 
+        // For sub-events, also include cross_event sections from the parent festival
+        if ($event->isSubEvent()) {
+            $parentCrossEventSections = $event->parent
+                ->festivalSections()
+                ->where('type', 'cross_event')
+                ->ordered()
+                ->get();
+
+            $sections = $parentCrossEventSections->merge($sections)->sortBy('sort_order')->values();
+        }
+
         return FestivalSectionResource::collection($sections);
     }
 
@@ -30,9 +41,39 @@ final class FestivalSectionController extends Controller
     {
         Gate::authorize('create', [FestivalSection::class, $event]);
 
-        $section = $event->festivalSections()->create($request->validated());
+        $data = $request->validated();
+        $redirectedToParent = false;
 
-        return $this->created(new FestivalSectionResource($section));
+        if (($data['type'] ?? 'standard') === 'cross_event') {
+            if ($event->isFlatEvent()) {
+                return $this->error(
+                    'Overkoepelende secties kunnen alleen worden aangemaakt bij festivals met programmaonderdelen.',
+                    422,
+                );
+            }
+
+            if ($event->isSubEvent()) {
+                $event = $event->parent;
+                Gate::authorize('create', [FestivalSection::class, $event]);
+                $redirectedToParent = true;
+            }
+        }
+
+        $section = $event->festivalSections()->create($data);
+
+        $response = $this->created(new FestivalSectionResource($section));
+
+        if ($redirectedToParent) {
+            $original = $response->getData(true);
+            $original['meta'] = [
+                'redirected_to_parent' => true,
+                'parent_event_name' => $event->name,
+            ];
+
+            return response()->json($original, 201);
+        }
+
+        return $response;
     }
 
     public function update(UpdateFestivalSectionRequest $request, Event $event, FestivalSection $section): JsonResponse
@@ -57,10 +98,10 @@ final class FestivalSectionController extends Controller
     {
         Gate::authorize('reorder', [FestivalSection::class, $event]);
 
-        foreach ($request->validated('sections') as $item) {
+        foreach ($request->validated('sections') as $index => $id) {
             $event->festivalSections()
-                ->where('id', $item['id'])
-                ->update(['sort_order' => $item['sort_order']]);
+                ->where('id', $id)
+                ->update(['sort_order' => $index]);
         }
 
         $sections = $event->festivalSections()->ordered()->get();