feat(documents) : filesystem storage, server-side pagination and PDF compression

- Add DocumentStorageService for file-based storage (replaces Base64 in DB)
- Add DocumentServeController with /file and /download endpoints
- Add DocumentUploadProcessor using FormData + filesystem storage
- Add DocumentNormalizer exposing fileUrl/downloadUrl on all responses
- Add DocumentFileCleanupListener for automatic file deletion
- Add MigrateDocumentsToFilesystemCommand (Base64 → files, memory-safe)
- Add ApiFilter (SearchFilter, ExistsFilter, OrderFilter) on Document entity
- Add PdfCompressorService + refactor CompressPdfCommand for batch processing
- Fix TypeMachine PUT: deserialize=false + validate=false to prevent
  UniqueEntity false positive and writableLink collection interference
- Update CHANGELOG for v1.8.0
- Update frontend submodule

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

src/Serializer/DocumentNormalizer.php

@@ -0,0 +1,61 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Serializer;
+
+use App\Entity\Document;
+use ArrayObject;
+use Symfony\Component\Serializer\Normalizer\NormalizerAwareInterface;
+use Symfony\Component\Serializer\Normalizer\NormalizerAwareTrait;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
+
+use function is_array;
+
+class DocumentNormalizer implements NormalizerInterface, NormalizerAwareInterface
+{
+    use NormalizerAwareTrait;
+
+    private const ALREADY_CALLED = 'DOCUMENT_NORMALIZER_ALREADY_CALLED';
+
+    /**
+     * @return null|array<string, mixed>|ArrayObject<int|string, mixed>|bool|float|int|string
+     */
+    public function normalize(mixed $data, ?string $format = null, array $context = []): array|ArrayObject|bool|float|int|string|null
+    {
+        $context[self::ALREADY_CALLED] = true;
+
+        /** @var null|array<string, mixed> $normalized */
+        $normalized = $this->normalizer->normalize($data, $format, $context);
+
+        if (is_array($normalized) && $data instanceof Document && $data->getId()) {
+            // Remove raw 'path' if present (never expose it to the client)
+            unset($normalized['path']);
+
+            // Always provide URL-based access
+            $normalized['fileUrl']     = '/api/documents/'.$data->getId().'/file';
+            $normalized['downloadUrl'] = '/api/documents/'.$data->getId().'/download';
+        }
+
+        return $normalized;
+    }
+
+    public function supportsNormalization(mixed $data, ?string $format = null, array $context = []): bool
+    {
+        if (isset($context[self::ALREADY_CALLED])) {
+            return false;
+        }
+
+        return $data instanceof Document;
+    }
+
+    /**
+     * @return array<class-string, bool>
+     */
+    public function getSupportedTypes(?string $format): array
+    {
+        return [
+            Document::class => false,
+        ];
+    }
+}