fix(security) : block SVG upload, enforce ROLE_CLIENT restrictions on documents

- Block SVG MIME type in TaskDocumentProcessor upload validation
- Serve existing SVG files as attachment (defense-in-depth) in download controller
- Block ROLE_CLIENT from uploading documents to tasks (only allowed via portal tickets)
- Add Doctrine extension to filter projects by allowedProjects for ROLE_CLIENT

Tickets: T-003, T-005, T-006

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

src/Doctrine/ProjectAllowedExtension.php

@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Doctrine;
+
+use ApiPlatform\Doctrine\Orm\Extension\QueryCollectionExtensionInterface;
+use ApiPlatform\Doctrine\Orm\Extension\QueryItemExtensionInterface;
+use ApiPlatform\Doctrine\Orm\Util\QueryNameGeneratorInterface;
+use ApiPlatform\Metadata\Operation;
+use App\Entity\Project;
+use App\Entity\User;
+use Doctrine\ORM\QueryBuilder;
+use Symfony\Bundle\SecurityBundle\Security;
+
+final readonly class ProjectAllowedExtension implements QueryCollectionExtensionInterface, QueryItemExtensionInterface
+{
+    public function __construct(
+        private Security $security,
+    ) {}
+
+    public function applyToCollection(QueryBuilder $queryBuilder, QueryNameGeneratorInterface $queryNameGenerator, string $resourceClass, ?Operation $operation = null, array $context = []): void
+    {
+        $this->addWhere($queryBuilder, $resourceClass);
+    }
+
+    public function applyToItem(QueryBuilder $queryBuilder, QueryNameGeneratorInterface $queryNameGenerator, string $resourceClass, array $identifiers, ?Operation $operation = null, array $context = []): void
+    {
+        $this->addWhere($queryBuilder, $resourceClass);
+    }
+
+    private function addWhere(QueryBuilder $queryBuilder, string $resourceClass): void
+    {
+        if (Project::class !== $resourceClass) {
+            return;
+        }
+
+        $user = $this->security->getUser();
+
+        if (!$user instanceof User) {
+            return;
+        }
+
+        // Only restrict for ROLE_CLIENT users who are NOT admins
+        if (!in_array('ROLE_CLIENT', $user->getRoles(), true) || in_array('ROLE_ADMIN', $user->getRoles(), true)) {
+            return;
+        }
+
+        $rootAlias = $queryBuilder->getRootAliases()[0];
+
+        $allowedProjectIds = $user->getAllowedProjects()->map(
+            fn (Project $project) => $project->getId(),
+        )->toArray();
+
+        if ([] === $allowedProjectIds) {
+            $queryBuilder->andWhere('1 = 0');
+
+            return;
+        }
+
+        $queryBuilder
+            ->andWhere($rootAlias.'.id IN (:allowed_project_ids)')
+            ->setParameter('allowed_project_ids', $allowedProjectIds)
+        ;
+    }
+}