There's currently no way to filter pull requests by WIP status. When we have a lot of open PRs, I can't quickly list all the ones that are still WIP or the ones that are actually done.

Similar to the "has pending reviews" and "has unfinished builds" filters, it would be nice to have an "is work in progress" filter on the PR list.

That way I can:

• See all the WIP PRs
• Check the "not WIP" state to get a clean list of finished PRs that are ready for review/merge.

This would be helpful