[BUG] Allow Ctrl+B passthrough for readline cursor navigation

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Ctrl-b is no longer backspace like it used to be. Non-destructive backspace.

bash prompt defaults to emacs control keys:
c-d delete char
c-b backspace
c-f forward
c-a beginning of line
c-e end of line
c-k kill to end of line
c-w delete word backwards
etc

It would be nice to retain those for those of us used to them. Thanks!

What Should Happen?

Ctrl-b should be non-destructive backspace

Error Messages/Logs

Steps to Reproduce

Start typing into prompt, type ctrl-b for backspace, nothing happens cursor does not move.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Not sure

Claude Code Version

2.1.50

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_