fix(security) : add role checks on Gitea API resources and all MCP tools

- GiteaBranch, GiteaBranchName, GiteaPullRequest: require ROLE_USER
- All 22 MCP tools: require ROLE_USER (ROLE_ADMIN for users/clients listing)

Tickets: T-002, T-007

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

src/Mcp/Tool/Task/CreateTaskTool.php

@@ -17,6 +17,8 @@ use App\Repository\UserRepository;
 use Doctrine\ORM\EntityManagerInterface;
 use InvalidArgumentException;
 use Mcp\Capability\Attribute\McpTool;
+use Symfony\Bundle\SecurityBundle\Security;
+use Symfony\Component\Security\Core\Exception\AccessDeniedException;
 
 use function sprintf;
 
@@ -33,6 +35,7 @@ class CreateTaskTool
         private readonly TaskGroupRepository $taskGroupRepository,
         private readonly TaskTagRepository $taskTagRepository,
         private readonly UserRepository $userRepository,
+        private readonly Security $security,
     ) {}
 
     public function __invoke(
@@ -46,6 +49,10 @@ class CreateTaskTool
         ?int $groupId = null,
         ?array $tagIds = null,
     ): string {
+        if (!$this->security->isGranted('ROLE_USER')) {
+            throw new AccessDeniedException('Access denied: ROLE_USER required.');
+        }
+
         $project = $this->projectRepository->find($projectId);
         if (null === $project) {
             throw new InvalidArgumentException(sprintf('Project with ID %d not found.', $projectId));
@@ -54,7 +61,6 @@ class CreateTaskTool
         $task = new Task();
         $task->setProject($project);
         $task->setTitle($title);
-        $task->setNumber($this->taskRepository->findMaxNumberByProjectForUpdate($project) + 1);
 
         if (null !== $description) {
             $task->setDescription($description);
@@ -104,8 +110,11 @@ class CreateTaskTool
             }
         }
 
-        $this->entityManager->persist($task);
-        $this->entityManager->flush();
+        $this->entityManager->wrapInTransaction(function () use ($task, $project): void {
+            $task->setNumber($this->taskRepository->findMaxNumberByProjectForUpdate($project) + 1);
+            $this->entityManager->persist($task);
+            $this->entityManager->flush();
+        });
 
         return json_encode([
             'id'          => $task->getId(),