feat(navidrome): add Subsonic REST API v1.16.1 compatible crate
Implements a new `rocksky-navidrome` crate providing a Navidrome/Subsonic
compatible API so any Subsonic client can browse and stream user-uploaded
audio. Auth uses the Bluesky handle as username and an existing API key
as password (plain, hex-encoded, or token/salt MD5).
Endpoints: ping, getMusicFolders, getArtists/getIndexes, getArtist,
getAlbum, getSong, stream (presigned S3 redirect), getCoverArt,
search3/search2, scrobble, updateNowPlaying, getAlbumList2/getAlbumList,
getRandomSongs, star, unstar. Both JSON and XML response formats are
supported. Start with `rockskyd navidrome` (default port 4533).