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.
- Introduced extension methods on IQueryable<TEntity> to filter entities
by Envelope (Id or Uuid) and Receiver (Id, EmailAddress, or Signature).
- Throws BadRequestException if no valid identifier is provided when notnull = true.
- Improves query handling consistency across application layer.
