- Introduce ActionPanel, EnvelopeInfoCard, TfaForm, ConfirmDialog, StatusPage, and Toast components for modular, presentational UI
- Add ToastService for pub/sub toast notifications; register in DI
- Refactor AccessCodeForm for improved UX and parameterization
- Enhance MainLayout with Toast integration and better error handling
- Standardize and extend app.css for new components and responsive design
- All new components are "dumb" (no service/API knowledge), using EventCallbacks for parent interaction
- ConfirmDialog supports awaitable user confirmation via TaskCompletionSource