TekH
87bdef9d5e
Introduce `SignCommand` and `SignCommandHandler` in the `EnvelopeGenerator.Application.Signature.Commands` namespace. - `SignCommand` is a CQRS command that encapsulates the envelope receiver's information (`EnvelopeReceiverDto`) and optional PSPDFKit annotation data. - Added computed properties for email template type (`TemplateType`) and receiver's email address (`EmailAddress`), with validation for null receivers. - `SignCommandHandler` implements the `IRequestHandler<SignCommand>` interface, with a placeholder `Handle` method delegating processing to pipeline behaviors. - Added necessary `using` directives for MediatR, DTOs, extensions, and constants.