ea4ab76724
docker:27-cli (Alpine) has no bash, only the POSIX /bin/sh (busybox ash). run: steps default to bash, so both steps in build-images failed immediately with "exec: bash: executable file not found in $PATH" - confirmed via the run's log right after the previous checkout fix landed. Both steps are already plain POSIX shell, so declare shell: sh as the job default instead of switching interpreters.