Port box's changelog-armed.sh as the first composite action, establishing
the pattern #6 and #7 copy: action.yml passes inputs as env vars, the
co-located script stays directly runnable, and the shared libs are sourced
relative to the action so they travel with it at the consumer's pinned ref.
Port deltas per issue #5: the version goes through version_read (#3) so the
guard works for package-json trees, and the bare-version emptiness check
consults changelog_section (#4) — the guard and the publisher cannot
disagree about what a section is. Messages and the header essay keep the
box#108 / rig#66 / rig#44 / cast#108 history; this is the guard rig and
cast regain at adoption.
CI gains an action-exercise job driving uses: ./actions/changelog-armed
against a scratch armed tree — the composite wiring proven, not just the
script.
Closes#5
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
