[RFC]: add support for shift-selection in the REPL

### Description

This RFC proposes adding support for selecting regions of the input using SHIFT+ARROW in the REPL. Julia supports this (attached below).

https://github.com/user-attachments/assets/402c9602-5578-4d51-afed-9a77db194187

### Related Issues

Related issues #2647.

### Checklist

- [X] I have read and understood the [Code of Conduct](https://github.com/stdlib-js/stdlib/blob/develop/CODE_OF_CONDUCT.md).
- [X] Searched for existing issues and pull requests.
- [X] The issue name begins with `RFC:`.

The issue does not identify a file, test, or entry point. Review related issue #2647 and the REPL input-handling implementation first; done should mean that SHIFT+ARROW selects regions of the input as demonstrated in the referenced Julia example.

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