Remove comments from backend and web-player source

Strip //, /* */ and XML doc comments from all backend .cs files, and
JS/TS/CSS/HTML comments from web-player source (.ts, .svelte, .css),
per the project's no-comments convention.

backend/Core/Musify.Application/Tracks/GetTrackStream.cs

@@ -9,8 +9,7 @@ using Musify.Application.Tracks.Responses;
 
 namespace Musify.Application.Tracks
 {
-    /// <param name="UserId">Null for an anonymous request — allowed only when
-    /// <see cref="PlaybackConfiguration.AllowAnonymousListening"/> is enabled.</param>
+
     public record GetTrackStreamQuery(Guid TrackId, long? UserId)
         : IQuery<ErrorOr<TrackStreamResponse>>;