Updated TestAnnotationController.Delete to extract the receiver signature from the envelope key
and pass it along with the envelope UUID when publishing RemoveSignatureNotification.
Returns BadRequest if the signature is missing.
- Introduced AnnotationCreateDto for creation-specific properties
- AnnotationDto now inherits from AnnotationCreateDto and includes Id, AddedWhen, ChangedWhen, and ChangedWho
- Added Type property to AnnotationCreateDto
- remove CreateAnnotationCommand
