Korean IME composition characters intermittently dropped while typing (Windows Terminal)

Description

While typing Korean text into the Claude Code prompt, characters that are mid-composition (초성/중성/종성 combining via the Korean IME) intermittently disappear/get dropped, especially during fast typing or while a response is streaming.

Environment

• Claude Code version: 2.1.208
• OS: Windows 11 Pro
• Terminal: Windows Terminal
• Shell: PowerShell (primary)

Steps to reproduce

1. Open Claude Code in Windows Terminal on Windows 11
2. Start typing Korean text using the Microsoft IME while a previous response is streaming, or while typing quickly
3. Observe that some composed characters are dropped/missing from the input

Expected behavior

All composed Korean characters should be preserved in the input buffer regardless of typing speed or concurrent terminal redraws.

Additional notes

This looks like it may be related to terminal redraw/repaint timing colliding with IME composition state (a known class of issue in terminal apps using raw-mode readline-style input with CJK IMEs). Toggling Windows Terminal's AtlasEngine rendering setting is a common workaround for similar issues in other apps, which may be worth investigating as a root cause on the Claude Code side as well.