CodeHubApp/CodeHub ? reverse-engineered prompt

Build me a polished iPhone and iPad app that lets me browse and manage my GitHub account in a clean, fast way. I want to sign in, see my repositories and organizations, open issues and pull requests, read repo details, and look through file diffs with the ability to comment on them. It should also include access to gists and a slide out menu style navigation so it feels easy to move around. Make it feel sleek and efficient, like a real GitHub companion app, not just a basic web view.

Use C# and Xamarin for iOS, and keep the app modern and responsive. If you need to check current GitHub or Xamarin docs while building it, go ahead and do that. Please also make the UI look good on both iPhone and iPad, and include a few sample screens or placeholder data if full API integration takes time.