Use when writing or reviewing C#/.NET tests with modern NUnit (4.x) — the constraint model, `Assert.EnterMultipleScope()`, lifecycle and parallelism attributes, data-driven tests, and running on Microsoft.Testing.Platform. Steers away from NUnit 2/3-era idioms (classic asserts, `Assert.Multiple(() => ...)`, format-string messages). Pairs with the tdd skill.
