mc#765 added `docker-cli` to the workspace-server Alpine runtime, but
the Alpine package is just the CLI binary — it does NOT include the
buildx plugin. Modern Docker (26.x in this image) defaults BuildKit=on,
so `docker build` immediately fails with:
local-build: pre-flight OK (docker=/usr/bin/docker)
Provisioner: workspace start failed for <id>: local-build mode:
ensure image for runtime "claude-code": local-build: docker build
molecule-local/workspace-template-claude-code:<sha>:
exit status 1: ERROR: BuildKit is enabled but the buildx component
is missing or broken.
Caught immediately after the mc#765 platform-image deploy + recreate
during the sdk-lead (360d42e4-8356-441c-80cf-16fcd5d5ce03) + CP-QA
(ec6cf05b-2637-4b3c-b561-b33914849aa2) recovery POST /restart calls.
Pre-flight passed (docker CLI present, confirmed by the line above),
but the actual `docker build` aborted on buildx-missing.
The fix mirrors mc#765's shape: add the matching Alpine package
(`docker-cli-buildx`, in community/, verified 0.14.0-r3 on alpine:3.20)
to the apk add line in workspace-server/Dockerfile. Diff is +1 word
in the apk-add line and a comment block extension that explains the
BuildKit/buildx requirement.
Related: mc#765 (parent fix), Task #194 / Issue #63 (local-build path).
hongming
e4a20e14d2