Each pair is a Music (Artist/Album/01 Title) or Soundtracks (Album/01 Title) library. The new Fixer tab takes the master, then the slave, through four reviewed steps: folder structure, album tags (optional MusicBrainz lookup; the slave reuses the fixed master's tags), folder names and file names, then links the two libraries. Every fix is an undoable operation. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>