Reusable CI for plain Python apps / locally-run tooling that don't deploy via
SAM or CDK. Beyond ruff lint/format + the conventions audit, it adds a
collect-only import check for a root suite whose live run needs secrets, and an
isolated full pytest run for a self-contained subproject dir (whose tests/
package would collide with the root tests/ under one rootdir).
Emits the org-required `ci / ci` via an aggregator job keyed `ci` that gates on
every other job. actionlint-clean.
