feat: convert Tidal tracks to Spotify ID immediately for lyrics

- Added SpotifyId field to Song model
- SquidWTFMetadataService now calls Odesli API when fetching track metadata
- Spotify ID is populated immediately when track is loaded, not during lyrics fetch
- GetLyrics now checks song.SpotifyId first before falling back to cache/Odesli
- Enables Spotify lyrics for all SquidWTF (Tidal) tracks automatically
- Reduces latency - conversion happens once during track load, not every lyrics request

allstarr/Models/Domain/Song.cs

@@ -44,6 +44,11 @@ public class Song
     /// </summary>
     public string? Isrc { get; set; }
     
+    /// <summary>
+    /// Spotify track ID (for lyrics and matching)
+    /// </summary>
+    public string? SpotifyId { get; set; }
+    
     /// <summary>
     /// Full release date (format: YYYY-MM-DD)
     /// </summary>