Change Track members: artwork -> std::string, genre -> TagLib::String, and add year
File::readFileTag now takes a Track& and fills artist/title/album/trackNr/year/genre/format/length
importFolder sets artwork to <folder>/cover.png
Rename Database::addSong to addTrack
Replace Metadata.h with Containers.h, introducing a HashTable
implementation with SIMD acceleration and specialized track tracking.
Cleanup PlayerEngine logic by merging it into the playback flow and
refactoring several internal API signatures.
Add Database class with SQLite fetch/fetchAlbum methods. Refactor
PlaybackEngine (data callback, seek, getPosition, decoder lifecycle)
and Player API (PlaybackEngine member, queue handling, PlayerLocal).
Update Metadata::Track fields to include artist/title/album/trackNr/length.
fegger