feat(bookstack) : add BookStackShelf API resource for listing shelves

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

src/State/BookStackShelfProvider.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\State;
+
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProviderInterface;
+use App\ApiResource\BookStackShelf;
+use App\Exception\BookStackApiException;
+use App\Service\BookStackApiService;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+
+final readonly class BookStackShelfProvider implements ProviderInterface
+{
+    public function __construct(
+        private BookStackApiService $bookStackApiService,
+    ) {}
+
+    public function provide(Operation $operation, array $uriVariables = [], array $context = []): array
+    {
+        try {
+            $shelves = $this->bookStackApiService->listShelves();
+        } catch (BookStackApiException $e) {
+            throw new BadRequestHttpException($e->getMessage(), $e);
+        }
+
+        return array_map(static function (array $shelf): BookStackShelf {
+            $dto       = new BookStackShelf();
+            $dto->id   = $shelf['id'] ?? 0;
+            $dto->name = $shelf['name'] ?? '';
+
+            return $dto;
+        }, $shelves);
+    }
+}