feat(skeleton) : wire skeleton writes to SkeletonStructureService

ModelType.setStructure() now stores data in pendingStructure instead of
writing to JSON columns. A new ModelTypeProcessor intercepts API Platform
POST/PUT/PATCH operations and delegates skeleton writes to
SkeletonStructureService, which persists to relation tables.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/State/ModelTypeProcessor.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\State;
+
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProcessorInterface;
+use App\Entity\ModelType;
+use App\Service\SkeletonStructureService;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Component\DependencyInjection\Attribute\Autowire;
+
+final class ModelTypeProcessor implements ProcessorInterface
+{
+    public function __construct(
+        #[Autowire(service: 'api_platform.doctrine.orm.state.persist_processor')]
+        private readonly ProcessorInterface $decorated,
+        private readonly SkeletonStructureService $skeletonStructureService,
+        private readonly EntityManagerInterface $entityManager,
+    ) {}
+
+    /**
+     * @param array<string, mixed> $uriVariables
+     * @param array<string, mixed> $context
+     */
+    public function process(mixed $data, Operation $operation, array $uriVariables = [], array $context = []): mixed
+    {
+        if (!$data instanceof ModelType) {
+            return $this->decorated->process($data, $operation, $uriVariables, $context);
+        }
+
+        $pendingStructure = $data->getPendingStructure();
+
+        // Persist the entity first (handles all non-skeleton fields)
+        $result = $this->decorated->process($data, $operation, $uriVariables, $context);
+
+        // If structure was provided in the payload, write it to skeleton relation tables
+        if (null !== $pendingStructure) {
+            $this->skeletonStructureService->updateSkeletonRequirements($data, $pendingStructure);
+            $data->clearPendingStructure();
+            $this->entityManager->flush();
+        }
+
+        return $result;
+    }
+}