Drop the pull_request trigger (the branch push already validates the commit),
drop the second npm run build from the lint job (the image build compiles it),
and build the image on arm64 after the cheap checks pass. The CI publishes it
as inputs-<hash>, so the merge to main only re-tags it.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
