Introduced the ability to share envelopes in read-only mode and view them via a dedicated page. Added `ShareEnvelopeReadOnlyAsync` in `AuthService.cs` to handle sharing logic. Updated `ReceiverPage.razor` with a "Share" button, popup UI, and validation for sharing inputs. Created `ReceiverReadOnlyPage.razor` for read-only document viewing with error handling and lifecycle management.
Added `EnvelopeKeyRedirectController.cs` to support legacy link redirection. Enhanced `ReadOnlyController.cs` to support envelope sharing with improved logging and `IMediator` integration. Improved state management, validation, and error handling across components. Performed general code cleanup and UI enhancements for better user experience.