Introduce `PostPublicViewMessage` and `PostPublicViewMessageHandler` to handle external user views on public links by applying workflow transitions. Integrate with `WorkflowViewSendPublicController` and add relevant tests.
- create an event subscriber to catch the workflow which arrive to a "sentExternal" step;
- add a messenger's message to handle the generation of the email;
- add a simple message, and a simple controller for viewing the document
- add dedicated tests
Introduce MessageBus to handle post-signature operations asynchronously. This ensures that further steps are executed through dispatched messages, improving system scalability and performance. Implement new handlers and messages for the workflow state transitions.