- Add update_tags() method to MetadataHandler for writing arbitrary tag
changes to MP3/M4A/FLAC/OGG files (title, artist, album, album_artist,
genre, date, track/disc number, comment, cover art)
- New MetadataEditorDialog (QDialog) with: cover art preview (drag-drop,
click-to-change, remove), form fields for all common tags, F2 / context
menu / toolbar button integration
- Batch editing: select multiple tracks to edit common fields (title and
track numbers hidden), mixed values shown as placeholder
- Search now filters across Artist, Title, and Album columns
- Fix: layout warning from double setLayout in dialog
- Fix: cover cache invalidation after metadata edit
- Fix: missing QDialog import causing crash in shortcut remapping
- Add F2 hotkey default for Edit Metadata action
