The CI runner's base image doesn't ship cmake (build failed with "cmake executable not found on PATH" during emcmake), and only bison was ever explicitly installed - curl and python3 happened to work by luck of the current runner image, not because the workflow guarantees them. Install the full README-documented toolchain explicitly in both the build and publish jobs. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>