feat: Add API endpoint to list node files

Implement issue #2719 - Add API endpoint to list project files

- Add GET /v3/projects/{project_id}/nodes/{node_id}/files endpoint
- Add list_node_files() method to Project class
- Add security checks to prevent path traversal
- Filter out .ghost temporary files
- Return file paths with MD5 checksums
- Require Node.Audit privilege

This allows users to discover dynamically created files
such as QEMU disk images created via the disk image API.

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

gns3server/api/routes/compute/projects.py

@@ -192,6 +192,20 @@ async def get_compute_project_files(project: Project = Depends(dep_project)) ->
     return await project.list_files()
 
 
+@router.get("/projects/{project_id}/nodes/{node_type}/{node_id}/files", response_model=List[schemas.ProjectFile])
+async def get_compute_node_files(
+    node_type: str,
+    node_id: str,
+    project: Project = Depends(dep_project)
+) -> List[schemas.ProjectFile]:
+    """
+    Return files belonging to a specific node.
+    """
+
+    node_path = f"project-files/{node_type}/{node_id}"
+    return await project.list_node_files(node_path)
+
+
 @router.get("/projects/{project_id}/files/{file_path:path}")
 async def get_compute_project_file(file_path: str, project: Project = Depends(dep_project)) -> FileResponse:
     """