Access to mocked stdin instance

Any chance we can get access to mocked stdin instance so we can restore standard input to original state with [`restore`](https://github.com/caitp/node-mock-stdin#mockstdinrestore)?

Start by locating the stdin-mocking entry point and reviewing the linked node-mock-stdin restore API. Trace how the mocked stdin instance is created and exposed, then verify that callers can access it and restore the original standard input; add or run the relevant tests if the repository provides them.

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