Jellyfin Playlist Membership — Easily browse Jellyfin Music song titles to add or remove from playlists

I wanted to quickly see which of my song titles are already in which playlists, and to quickly add them to other playlists or remove them etc. There is just no view that does this inside Jellyfin, and neither in Music Assistant nor Navidrome. You can do it by opening and closing each one, but that is very messy and time-consuming. I iterated through something with Claude Code to create a simple HTML file that allows me to do this much quicker and slicker now. It also has some sort functionality, and you can play a track to hear it, and even delete it from your library to clean things up. As I have multiple folders on Jellyfin Music that separate radio shows, there is also an option filter for folders at the top of the screen. Hopefully this helps others who have had a similar challenge and wondered why this was not a built-in feature. See https://github.com/Danie10/jellyfin-playlist-membership