Updated several C# controllers to use the new
`DigitalData.Core.Abstraction.Application.DTO` namespace
and removed references to `DigitalData.Core.DTO`. Added
`[Obsolete("Use MediatR")]` attributes to indicate a shift
towards MediatR for request handling. Improved error
handling and code organization in key methods. Updated
Razor view files to reflect namespace changes for
consistency across the application.
TekH
fcbe956095