Three issues fixed:
1. Plex add-track used delete+recreate (Playlist.create) which was
unreliable — switched to addItems() which atomically appends the
track without touching existing playlist items.
2. After a successful add, the UI only did an optimistic local update.
On reopen the automatic matcher ran fresh and couldn't connect the
manually selected track to the source slot, making it look unfixed.
Now both add and replace re-fetch the compare view from the server
so the matcher sees the actual updated Plex state.
3. Matching algorithm was too strict for common title variants. Added
_norm_title() which strips feat./ft., remaster/remastered, and
edition qualifiers before comparison — so "Boy 1904" matches
"Boy 1904 (2019 Remaster)" and "Float Away" matches "Float Away
(feat. Flamingosis & Eric Benny Bloom)". Display titles unchanged.