Windows: IME (Korean/Japanese) input broken after Alt-Tabbing back

Description

After switching to another window and coming back to Claude Code on Windows, the IME (Input Method Editor) stops working. Users cannot switch between English and Korean/Japanese input methods. The IME state becomes desynchronized when the terminal regains focus.

Environment

• OS: Windows 11 Pro for Workstations
• Input Method: Korean IME, likely affects Japanese IME as well

Steps to Reproduce

1. Open Claude Code in the terminal
2. Type normally in Korean (or any IME-based language) — works fine
3. Alt-Tab (or click) to switch to another window
4. Switch back to Claude Code
5. Attempt to toggle IME (e.g., Han/Eng key) — input method does not switch

Expected Behavior

IME state should be preserved or re-synced when the terminal window regains focus.

Workarounds Attempted

• Ctrl+Shift or Win+Space — inconsistent
• Pressing Alt to reset IME — not possible on keyboards without Alt key

Additional Context

• This does NOT occur in Codex (OpenAI CLI), suggesting it's specific to how Claude Code handles terminal input/focus events.
• Significant usability blocker for non-English users who rely on IME daily.