Feature Request - Allow users to mark problems, contests etc as fav

[l3456]

Clist is the best to track our progress across multiple sites, but I guess it's mostly read only.

I would love to see a feature where users can interact with problems, contests etc. like allowing users to mark a problem as favourite, todo, solved and maybe add some info around it like adding a note or personal tags.

At the very least, allowing users to mark a problem as already solved would be very useful as currently clist doesn't detect solves correctly across all sites.