* fix(windows): stop subprocess console-window popups + add CI guard
The single biggest source of Windows 'terminal popup' bug reports was bare
subprocess.run/Popen calls spawning a console window. The compat helpers
(windows_hide_flags / windows_detach_popen_kwargs) already existed but the
footgun checker had no rule to stop new bare calls from reintroducing the flash.
- scripts/check-windows-footguns.py: new AST-based rule flagging subprocess
calls that can create a new console — output-redirection-aware (capture/
redirect/check_output exempt) and POSIX-only-program-aware (launchctl/
systemctl/brew/etc. exempt). Comprehensive on real popups, no annotation
burden on calls that can't flash.
- Swept all genuine window-spawning sites through windows_hide_flags()/
windows_detach_popen_kwargs(); marked intentionally-visible launches
(editor/terminal/foreground re-exec) with '# windows-footgun: ok'.
- tests/scripts/test_windows_footgun_subprocess_rule.py: behavior-contract
tests + full-repo cleanliness invariant.
- CONTRIBUTING.md: documents the rule + the helper pattern.
* test: accept creationflags kwarg in psutil_android fake_subprocess_run
The Windows no-window sweep added creationflags=windows_hide_flags() to
install_psutil_android.py's subprocess.run call; the test's fake stub had a
fixed (cmd) signature and raised TypeError on the new kwarg.
