Paperclip: Stored XSS via javascript: URLs in MarkdownBody — urlTransform override disables react-markdown sanitization

Summary MarkdownBody, the shared component used to render every Markdown surface in the Paperclip UI issue documents, issue comments, chat threads, approvals, agent details, export previews, etc., passes urlTransform=url = url to react-markdown. That override replaces react-markdown's built-in...