[FEATURE] just use `sh`, not bash

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When working on minimalist systems or on BSD's such as OpenBSD, it would be useful if Claude Code made use of sh (e.g. ksh) without the bash dependency.

Proposed Solution

I would like to run on systems that don't have bash without installing bash.

Alternative Solutions

Install bash.

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_