[Windows] Buffered keypress auto-approves plan/permission prompts after window switch or login

Environment: Windows 11, Claude Code VSCode extension, claude-sonnet-4-6

Steps to reproduce:

1. Have a plan-mode approval prompt or permission dialog active in Claude Code
2. Switch to another Windows application (or lock/unlock the screen)
3. Return to Claude Code — a buffered Enter keypress auto-approves the prompt without user review

Expected: Approval prompts should require deliberate user input after focus returns.

Actual: Claude Code treats the buffered keypress as an approval and immediately begins executing the plan/action.

Impact: Work executes without explicit user consent, which is especially problematic for destructive or hard-to-reverse operations (file edits, git commits, etc.).