The first image build failed in build-gitea: the --chmod option requires BuildKit Both Dockerfiles declare `# syntax=docker/dockerfile:1` and use `COPY --chmod`, but gcr.io/cloud-builders/docker runs the legacy builder unless DOCKER_BUILDKIT=1 is set. The image ships the buildx plugin, so setting it on the two build steps is all that is needed. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>