[BUG] Korean characters corrupted when using /export on Windows

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?

When using the /export command to copy conversation to clipboard on Windows, Korean characters (and likely other non-ASCII characters) are corrupted. The UTF-8 encoded text appears to be decoded with the wrong character
encoding, resulting in garbled output.

Example:

• Original text: 한글 내보내기할때 글자가 깨지는데 테스트용 메시지임
• Exported text: ?쒓? ?대낫?닿린?좊뻹 湲?먭? 源⑥??붾뜲 ?뚯뒪?몄슜 硫붿떆吏??

What Should Happen?

The /export command should preserve UTF-8 encoding when copying to clipboard, so Korean (and all Unicode) characters display correctly when pasted into any application.

Expected output should be identical to what appears in the Claude Code interface.

Error Messages/Logs

No error messages are shown. The command reports success:
  Conversation copied to clipboard

  However, the clipboard content shows corrupted Korean characters throughout the exported conversation.

Steps to Reproduce

1. Start a conversation in Claude Code on Windows
2. Type a message containing Korean characters (e.g., 한글 테스트)
3. Run the /export command
4. Paste the clipboard content into any text editor
5. Observe that Korean characters are corrupted/garbled

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.42

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_