Push builds have been RED on the lint step since ~build 209 from accumulated
formatting drift. This is the mechanical cleanup: ruff format + ruff --fix
(UP038 isinstance unions, SIM105 contextlib.suppress, UP031 f-strings, SIM115
tempfile context manager), shfmt -i 2 -ci, nixpkgs-fmt/statix/deadnix (merged
attrsets, dropped unused lib args), yamllint, and shell quoting fixes in
tests/lasuite-docs/setup_custom_tests.sh. No behaviour changes intended;
lint: PASS, unit tests: 138 passed.
Port from terraform-hetzner branch. Adds the Hetzner cc-ci flake host with
all 3 root authorized keys so nixos-rebuild doesn't lock out SSH access.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
