94f095e8b7
check_subprocess_stdin.py already had a full-repo-scan pytest wrapper (test_subprocess_stdin_guard.py), so a plain pytest run catches a regression there without anyone remembering to run the script by hand. check-windows-footguns.py had no equivalent (only a narrow single-rule test existed), which is why the bare os.killpg/ signal.SIGKILL regression in the npx-agent-browser hardening commit shipped past local testing and was only caught by CI running the script directly. New test_windows_footguns_full_repo_scan.py mirrors the stdin guard's exact pattern to close that asymmetry. Also adds direct coverage for _kill_process_tree's getattr fallback when os.killpg is missing, and asserts warm_agent_browser_npx_cache's Popen call passes stdin=subprocess.DEVNULL as a literal argument.