Complete .NET 10 project setup with Next.js frontend and comprehensive C# testing infrastructure using Playwright, Reqnroll (BDD), and NUnit. Use when creating a new full-stack project that requires (1) .NET backend/testing with Next.js frontend, (2) End-to-end testing with Playwright in C#, (3) BDD testing with Reqnroll/SpecFlow patterns, (4) NUnit test framework setup, or (5) VS Code configuration for .NET testing workflow.