Refactored Envelope, Receiver, and Signature entity classes to eliminate preprocessor directives around class and property definitions. Applied attributes directly and reformatted properties for clarity. Constructors are now always present, with default initializations still conditional where needed. Removed obsolete directives from IHasAddedWho. These changes improve code readability, maintainability, and cross-platform compatibility.
Introduced interfaces for audit fields (AddedWhen, ChangedWhen, ChangedWho, AddedWho) and updated domain entities to implement them. Adjusted properties for consistency and nullability. Updated MappingProfile to map audit fields between DTOs and entities. Improves auditability and standardization across the domain model.
