Refactored the Role class by introducing a nested static Receiver class containing PreAuth and FullyAuth constants. Marked the original Role.PreAuth and Role.FullyAuth as [Obsolete] with guidance to use the new Receiver constants. Added a conditional using directive for System for NETFRAMEWORK compatibility.
Replaced all usages of ReceiverRole with the new Role class in EnvelopeGenerator.Domain.Constants. Removed ReceiverRole.cs and added Role.cs with PreAuth and FullyAuth constants. Updated all [Authorize] attributes and role checks in controllers and authentication logic to use Role.FullyAuth and Role.PreAuth. This centralizes role management for improved maintainability and clarity.
