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/Contracts/IStreamTicketService.cs

@@ -2,11 +2,7 @@ namespace Musify.Application.Contracts
 {
     public interface IStreamTicketService
     {
-        /// <param name="userId">Null for an anonymous listener — the ticket is issued without a
-        /// <c>sub</c> claim.</param>
-        /// <param name="keyPrefix">The storage key (prefix) the ticket authorizes reading from.</param>
-        /// <param name="maxBytes">When set, the Streaming Gateway clamps the byte range it will serve
-        /// for this ticket to <c>[0, maxBytes)</c> — used for the anonymous preview fragment.</param>
+
         StreamTicket IssueTicket(long? userId, string keyPrefix, long? maxBytes = null);
     }