Added `EnvelopeSenderPage.razor` as a placeholder for the sender's dashboard.
Updated `Index.razor` to include a homepage with a hero header, feature badges,
and dynamic description rendering using JavaScript interop.
Implemented `LoginReceiverPage.razor` for secure document access via access code,
with error handling and user feedback for various login states.
Implemented `LoginSenderPage.razor` for sender authentication, including error
handling, password visibility toggle, and redirection to the sender dashboard.
Introduced a new Blazor WebAssembly project (`EnvelopeGenerator.WebUI.Client`) targeting .NET 8.0 for client-side functionality.
Added a Blazor Server project (`EnvelopeGenerator.WebUI`) to host the application and enable server-side rendering.
Created essential Razor components (`MainLayout.razor`, `Home.razor`, `Routes.razor`, `Error.razor`, etc.) for layouts, routing, and error handling.
Configured project files, solution structure, and build settings. Added necessary styles, app settings, and launch profiles for development.
