Refactored `DocSignedNotification` to remove inheritance from
`EnvelopeReceiverDto` and introduced a required `EnvelopeReceiver`
property. Updated all usages across the codebase to align with the
new structure, including controllers, handlers, and tests.
- Improved encapsulation and reduced coupling by making
dependencies explicit.
- Updated `AnnotationController`, `DocStatusHandler`,
`HistoryHandler`, and `SendSignedMailHandler` to use the
`EnvelopeReceiver` property.
- Adjusted `DocSignedNotificationTests` to reflect the new
instantiation pattern.
- Updated XML documentation and ensured consistent access to
`EnvelopeReceiver` properties like `EnvelopeId`, `ReceiverId`,
and `EmailAddress`.
- Introduced new record `PsPdfKitAnnotation` to encapsulate both Instant and Structured annotation data
- Updated `DocSignedNotification` to use `PsPdfKitAnnotation` instead of `ExpandoObject Annotations`
- Modified extension methods to accept and map `PsPdfKitAnnotation`
- Added reference to `EnvelopeGenerator.Application.Annotations.Commands` for `CreateAnnotationCommand`
- Added `RealEmailTemplates` property with predefined email templates.
- Populated the repository with these templates in the `Setup` method.
- Ensures tests have consistent, realistic email data available.
