feat(DocSignedNotification): replace Annotations with PsPdfKitAnnotation in DocSignedNotification

- 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`

EnvelopeGenerator.Web/wwwroot/js/app.js

@@ -250,8 +250,8 @@ class App {
                 // Export annotation data and save to database
                 try {
                     const res = await signEnvelope({
-                        psPfKitInstant: iJSON,
-                        psPfKitStructured: mapSignature(iJSON)
+                        instant: iJSON,
+                        structured: mapSignature(iJSON)
                     });
 
                     if (!res.ok) {