Vietnamese language input not processing correctly in CLI

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?

on typeing in input vietnamese language is bug word

What Should Happen?

on typeing in input vietnamese language is bug wor

Error Messages/Logs

Steps to Reproduce

<img width="850" height="176" alt="Image" src="https://github.com/user-attachments/assets/d6cb6897-4965-4d0d-87d3-a08f2fade646" />

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.12

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Cursor

Additional Information

_No response_