setup.sh is a curl-able one-shot installer for the Pi workstation
harness (snowspeeder/harness): prompts for the Gitea username and
password (or reads GITEA_USER/GITEA_PASS), verifies them, downloads
the harness archive and runs its install.sh --yes.
Portable across macOS and Linux (bash 3.2+); reattaches stdin to
/dev/tty so the prompts work even when piped via curl | bash. Extra
arguments pass through to install.sh.
