Chrome processes not cleaned up after execution on Windows

Bug

On Windows 11, Codex CLI leaves orphaned Chrome processes running after codex exec completes. These processes consume significant CPU until manually killed.

Environment

• OS: Windows 11
• Codex CLI: latest (npm global)
• Shell: git-bash (MSYS)

Steps to reproduce

1. Run codex exec "..." on Windows
2. After execution completes, check Task Manager
3. Chrome processes remain running with high CPU usage

Expected behavior

Chrome processes spawned by Codex should be terminated when execution completes.

Actual behavior

Orphaned Chrome processes persist, consuming high CPU. Requires manual kill.

Workaround

Manually kill Chrome processes after Codex execution completes.