Galad/tranquire ? reverse-engineered prompt

Build me a .NET web UI automation framework that uses the screenplay style for acceptance tests, inspired by Serenity BDD.

I want a clean core library for modeling user actions and questions in a way that makes tests readable and easy to maintain, plus a Selenium based layer for automating a browser UI. Also include a small NUnit helper so assertions fit naturally into the test flow.

Please add a simple demo app for a Todo list and a set of acceptance tests that show how the framework is meant to be used against both the UI and an API level test setup. Keep the code organized so the framework and the demo are separate, and make sure the whole solution builds and tests from the command line.

If you need to check current docs or best practices for Selenium or .NET testing, look them up online as you go.