feat(ui): add Genre column as optional field in playlist table view

Added genre as a toggleable column in the playlist songs table. The Genre column
displays genre information for each song in playlists and is available through
the column toggle menu but disabled by default.

Implements feature request from GitHub discussion #4400.

Signed-off-by: Deluan <deluan@navidrome.org>

ui/src/playlist/PlaylistSongs.jsx

@@ -169,6 +169,7 @@ const PlaylistSongs = ({ playlistId, readOnly, actions, ...props }) => {
       quality: isDesktop && <QualityInfo source="quality" sortable={false} />,
       channels: isDesktop && <NumberField source="channels" />,
       bpm: isDesktop && <NumberField source="bpm" />,
+      genre: <TextField source="genre" />,
       rating: config.enableStarRating && (
         <RatingField
           source="rating"
@@ -190,6 +191,7 @@ const PlaylistSongs = ({ playlistId, readOnly, actions, ...props }) => {
       'playCount',
       'playDate',
       'albumArtist',
+      'genre',
       'rating',
     ],
   })