VS Code extension terminal does not handle Cmd key and Korean IME toggle key (한영키)

Environment

• OS: macOS (Darwin 24.6.0)
• Claude Code: VS Code extension
• Keyboard: Mac Korean keyboard layout

Bug Description

When using Claude Code inside the VS Code integrated terminal:

1. Korean IME toggle key (한영키): Pressing the 한/영 key types 57358u as text instead of switching the input method.
2. Cmd+Q: Pressing Cmd+Q types q instead of quitting. The Cmd modifier key is not recognized.

Both issues only occur in the Claude Code VS Code extension terminal. Regular VS Code terminals handle these keys correctly.

Steps to Reproduce

1. Open Claude Code in VS Code (via extension)
2. Press the 한영 key → 57358u appears in the input
3. Press Cmd+Q → q is typed instead of quit

Expected Behavior

• 한영 key should switch input method (or be silently ignored)
• Cmd+Q should quit the application

Actual Behavior

• Raw keycodes/characters are inserted as text input