[BUG] IME (Korean input method) toggle does not work inside Claude Code terminal without switching focus

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?

Description

After updating to v2.1.96, switching between Korean and English input
using the IME toggle key (한/영 key — a dedicated hardware key on Korean
keyboards that switches between Hangul and Latin input modes at the OS level)
does not work while the cursor focus is inside the Claude Code terminal.
The input method change only takes effect after switching focus away
(e.g., Alt+Tab or clicking another window) and returning.

Steps to Reproduce

1. Open Claude Code terminal (Windows)
2. Press 한/영 key (Korean IME toggle key) to switch input mode
3. Expected: input method switches immediately (e.g., from English to Korean or vice versa)
4. Actual: IME toggle has no effect until focus leaves and returns to the terminal

Environment

• OS: Windows 11
• Claude Code version: v2.1.96
• Input method: Microsoft Korean IME (한/영 key)
• Interface: Claude Code TUI (terminal)

Expected Behavior

한/영 key should toggle the IME input mode immediately without requiring a focus switch.

Additional Context

This issue appeared after updating to v2.1.96.
Likely related to how the TUI captures raw keyboard input on Windows,
which may be intercepting or consuming the IME mode-switch event
before the OS can process it.

What Should Happen?

한/영 key should toggle the IME input mode immediately while
the Claude Code terminal is in focus, without requiring the user
to switch focus to another window and back.

Error Messages/Logs

No error messages. The IME toggle silently fails with no output.

Steps to Reproduce

1. Open Claude Code terminal on Windows
2. Start typing in English
3. Press 한/영 key (Korean IME toggle key) to switch to Korean input
4. Try to type Korean characters
5. Observe: characters still come out in English (IME did not switch)
6. Alt+Tab to another window, then Alt+Tab back to Claude Code
7. Observe: now Korean input works — the toggle was applied but delayed

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.1.96

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_