Generate Testability Wrappers skill: what it does and how to install it

What it does. Identifies an abstraction strategy from the static dependency and target framework, then generates wrapper interfaces, implementations, composition code and focused tests. It favours built-in .NET abstractions for time, HTTP and file systems, and uses scoped ambient overrides when static APIs must keep their signatures.

When to use it. When C# code needs a testable seam for an ambient or static dependency that is not already injected. It does not apply when the target already uses an interface or built-in abstraction, or when the task is to find statics or migrate call sites in bulk.