Make native systemd services the recommended production path for
pobsync while keeping Docker Compose available for development and
optional test installs.
Add web, worker, and scheduler systemd unit templates, a native
environment example, an optional nginx reverse proxy template, and an
installer that creates the venv, service user, env file, units, and
runs migrations/static collection.
Allow native deployments to configure POBSYNC_BACKUP_ROOT directly and
document the new production layout and update flow.
Peter van Arkel
b93e19a7c8