MP3 CSV Tagger v1.2.0

1.2.0 — 2026-10-15

• Undo (tag snapshots) — every Apply now writes a
  mp3tag_*.undo snapshot next to the change log holding the tags it
  replaced (never copies of the audio). mp3csvtagger undo / the
  Apply tab's "Undo a run…" restores them; files changed since the
  run are skipped unless forced.
• Export library → CSV — one row per file, one column per tag,
  plus FileName/FilePath/Folder. The location columns work as Match
  columns in any CSV (and can never be written — files are never
  renamed or moved).
• Tags from filenames & paths — {Tag} patterns capture values
  from names and folder layouts into a normal, undoable preview
  (GUI dialog + from-filename CLI).
• Library report — duplicate tracks and spelling variants
  (e.g. Beatles vs beatles); pick the spelling to keep and the
  fix is built as a preview. Nothing changes automatically.
• Role presets — saved column-role setups (JSON in
  ~/.mp3csvtagger/presets/) plus two built-ins; CSV tab controls,
  add-csv --preset, presets command.
• Cover art & lyrics — a Cover Art Write column embeds front
  covers from image paths (blank cell removes art, previewed and
  undoable); lyrics write correctly as USLT (a frame-construction
  bug that stored a list repr for string-text frames is fixed).
• MusicBrainz fill (opt-in) — fills only EMPTY Album / Year /
  Recording Date / Genre for files with Title + Lead Performer, at
  1 request/second, into the preview. Offline = clear error, no
  partial writes.
• Help — the in-app Help tab is now a 20-topic browser; the same
  text ships as docs/HELP.md (generated from helptext.py).
• Repository tidy-up: legacy material removed; the docs now describe
  the current program only.