Static URLs carry no version, but nginx served them with expires max, so
after an update or a theme change browsers kept the old CSS and JS. They
now revalidate each load (304 when unchanged). CI checks the header, the
304 and that a changed file is sent again.
- Comment out the nginx /socket.io/ location: a firewall on 6081 does not
protect a console that nginx proxies on 80/443.
- Default SOCKETIO_HOST to 127.0.0.1.
- README: short enable steps and the changes existing installs need.
- test_socketiod_disabled writes its settings module to a temporary
directory instead of the source tree.
- Add local ports and env var fallback for CSRF_TRUSTED_ORIGINS in settings.py.template
- Configure SECURE_PROXY_SSL_HEADER for reverse proxy / HTTPS environments
- Update Nginx proxy headers to use $http_host and $scheme to prevent port mismatch
