Port the GitHub CI gates (gofmt, go vet, golangci-lint, race tests with
the coverage profile, the 100% coverage gate, go build) to the shared
ci-workflows go.yaml. v* tags build the GoReleaser-equivalent archives
with scripts/build-release.sh and attach them with SHA256SUMS to the
Gitea release. The GitHub workflows ran on ubuntu-22.04/macos/windows
runners that Gitea does not serve; removed.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
