- _terminate_real_profile_chrome(): directly-launched real browsers are ours
to reap (agent-browser only attaches); wired into the atexit emergency
cleanup and both launch-failure paths so orphaned Chrome processes can't
accumulate.
- Display-less Linux gate: append --headless=new (shares the profile's normal
cookie store, unlike legacy headless) so the direct-launch path doesn't
regress servers without DISPLAY/WAYLAND_DISPLAY.
- Register browser.real_profile_pin in config_defaults.py and document the
new launch model + pin in website/docs/user-guide/features/browser.md.
- Drop unused tempfile import from the cherry-picked commit.
Teknium