Clean up Application layer commands/queries readability and correctness

Add missing AsNoTracking() on read-only queries, drop redundant
Update() calls on already-tracked entities, and fix inconsistent
formatting (stray spaces in generics, ternaries, and lambdas) across
the Albums/Tracks/PlayLists/Users command and query handlers.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

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

@@ -33,7 +33,7 @@ namespace Musify.Application.Tracks
             var pagedEntities = await tracksQuery
                 .OrderByDescending(t => t.Track.CreatedAt)
                 .ThenBy(t => t.Id)
-                .Select(t => new { t.Track, ListensCount = t.Track.ListeningHistories.Count } )
+                .Select(t => new { t.Track, ListensCount = t.Track.ListeningHistories.Count })
                 .ToPagedListAsync(request.PageNumber, request.PageSize, totalCount, cancellationToken);
 
             var items = pagedEntities