scripts/check-phase16.sh runs the layer unit tests, the layer playground SSR smoke, the site app install/build/tests/smokes, the host boot tests, the grzyby command tests with -race and check-deploy. Each stage fails on not ok, fail/skip/todo/cancelled counts, missing named tests, go test failures, skips, no tests to run, data races or a smoke without ok; it ends with "Phase 16 gate passed".