Skip metadata refresh for already-indexed items during validation

Optimizes the validation process by checking if items already exist in
the database before attempting to refresh metadata.

Emby.Server.Implementations/Library/Validators/MusicGenresValidator.cs

@@ -1,6 +1,9 @@
 using System;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+using Jellyfin.Data.Enums;
+using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Library;
 using MediaBrowser.Controller.Persistence;
 using Microsoft.Extensions.Logging;
@@ -45,17 +48,25 @@ public class MusicGenresValidator
     public async Task Run(IProgress<double> progress, CancellationToken cancellationToken)
     {
         var names = _itemRepo.GetMusicGenreNames();
+        var existingMusicGenreIds = _libraryManager.GetItemIds(new InternalItemsQuery
+        {
+            IncludeItemTypes = [BaseItemKind.MusicGenre]
+        }).ToHashSet();
 
         var numComplete = 0;
         var count = names.Count;
+        var refreshed = 0;
 
         foreach (var name in names)
         {
             try
             {
                 var item = _libraryManager.GetMusicGenre(name);
-
-                await item.RefreshMetadata(cancellationToken).ConfigureAwait(false);
+                if (!existingMusicGenreIds.Contains(item.Id))
+                {
+                    await item.RefreshMetadata(cancellationToken).ConfigureAwait(false);
+                    refreshed++;
+                }
             }
             catch (OperationCanceledException)
             {
@@ -75,6 +86,8 @@ public class MusicGenresValidator
             progress.Report(percent);
         }
 
+        _logger.LogInformation("Refreshed metadata for {RefreshedCount} new music genres out of {TotalCount} total", refreshed, count);
+
         progress.Report(100);
     }
 }