OptionalenvDefaults to process.env.
OptionalinteractiveThe --interactive / --no-interactive flag value, when the caller passed one.
undefined means "not specified" — that is what lets detection run.
OptionalstdinDefaults to process.stdin.isTTY. A prompt needs a real stdin to read from.
OptionalstdoutDefaults to process.stdout.isTTY. A prompt needs a real stdout to render on.
Inputs to ResolveInteractivity. Every field is injectable for tests.