Port the build pipeline from the splat sibling project. Instead of
triggering on git tags, the image now builds when
config/initializers/version.rb changes on main — a version bump IS the
release — plus a workflow_dispatch button for manual builds.
Reads Clinch::VERSION, tags the image :vX.Y.Z, and moves :latest only
for non-pre-release versions. Also builds multi-arch (amd64 + arm64) on
native runners and stitches a manifest, replacing the amd64-only build.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Builds the production Docker image and pushes it to
ghcr.io/dkam/clinch on pushes to main (edge + sha tags) and on v*
release tags (vX.Y.Z, vX.Y, latest). amd64 only, with GHA layer caching.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
