Add pull request label filtering

[areibman]

Add label filtering to pull requests to enable quick navigation and organization of PRs by their categories and statuses.

This PR introduces a comprehensive label filter with multi-select capabilities, various logic options (OR, AND, NOT, ONLY), and an option to include PRs without labels. The filter state persists across sessions, and label counts are displayed dynamically to enhance workflow efficiency.

---

 

Fixes #32

[cursor[bot]]

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch. _{Learn more about Cursor Agents}