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.

backend/Core/Musify.Application/Users/CreateUser.cs

@@ -28,7 +28,7 @@ namespace Musify.Application.Users
     }
 
     public class CreateUserCommandHandler(IDatabase database, ILogger<CreateUserCommandHandler> logger)
-        : ICommandHandler<CreateUserCommand, ErrorOr<UserApplicationResponse> >
+        : ICommandHandler<CreateUserCommand, ErrorOr<UserApplicationResponse>>
     {
         public async ValueTask<ErrorOr<UserApplicationResponse>> Handle(CreateUserCommand request, CancellationToken cancellationToken)
         {