migrate-legacy-ci

Decide what to do with one of unional's repos still on a legacy CI shape — a single nodejs.yml calling typescript-build.yml/typescript-test.yml/npm-release.yml, or inlined yarn steps — and then archive it, drop its CI, or migrate it to the pull-request.yml + release.yml split. Use before **apply-repo-baseline** touches a repo, when a ruleset would require code / all-checks on a pipeline that cannot produce it, when asked to 'migrate the old workflows', 'fix nodejs.yml', 'why is this PR unmergeable', or when auditing which repos are on the old pipeline.