Introduced a new feature to allow users to reject envelopes with an optional reason. Added a `RejectAsync` method in `AnnotationService` to handle rejection requests. Updated `ReceiverPage.razor` to include a "Reject" button in the PDF toolbar and a rejection popup for user input.
Implemented state management for the rejection popup, including visibility, submission status, and validation messages. Updated `AnnotationController` to accept `envelopeKey` as a route parameter for the rejection endpoint. Modified `ReceiverClaimExtensions` to support multiple email claim types.
Added new CSS styles for the "Reject" button, including hover effects and dark theme support. Enhanced error handling and logging for the rejection process.