Migrate to yandex-music-api-go v0.0.0-20261018120746-dbf9a46bb2e7

Library now provides GetTrackDownloadURL (signed URL via XML download_info_url),
so ym-dl delegates to it instead of reimplementing XML parsing and MD5 signing.
Removed local DownloadTrackXML/DownloadInfoXML and unused crypto/md5, encoding/hex,
encoding/xml, io imports from client.go.

Track.Lyrics replaced by LyricsInfo (availability flags only, no text).
Lyrics text requires separate GetTrackLyrics + GetTrackLyricsText calls —
not implemented yet, lyrics field left empty.

internal/storage/storage.go

@@ -584,9 +584,12 @@ func BuildTrackMetaFromYandex(track *yandexmusic.Track, album *yandexmusic.Album
 	}
 
 	// Lyrics
+	// Note: track.LyricsInfo only contains availability flags, not the text.
+	// To fetch full lyrics text, call yandexClient.GetTrackLyrics + GetTrackLyricsText separately.
 	var lyrics string
-	if track.Lyrics != nil && track.Lyrics.HasText {
-		lyrics = track.Lyrics.Text
+	if track.LyricsInfo != nil && track.LyricsInfo.HasAvailableTextLyrics {
+		// Lyrics text available but not fetched here — requires separate API call
+		lyrics = ""
 	}
 
 	return TrackMeta{