Playlist label indicator

[Kevincho26]

I think this would be a perfect companion feature for Tagify. Being able to instantly see which playlists a song is already in would be incredibly useful for building and maintaining a clean playlist catalog.

It could help users avoid duplicates and reduce redundancy across their playlists, which would make music organization much more practical.

This archived project could be a great reference or starting point, since the original author made it public for others to fork and continue:
https://github.com/duffey/spicetify-playlist-labels?tab=readme-ov-file