[grade=A] ci(docker): pass release VERSION as build-arg to Dockerfile

Docker Hub job verified the v${VERSION} .deb URL (correct), then built
the image without --build-arg, so packaging/docker/Dockerfile used its
stale ARG VERSION=6.2.4 default and fetched the v6.2.4 daemon .deb.
Releases without a v6.2.4 asset 404 (curl 22, seen on v6.2.6.6); worse,
releases where the old asset exists would silently ship a Docker image
containing the OLD daemon under the NEW version tag.

Judge: codex exec grade A.

.github/workflows/distribute.yml

@@ -87,6 +87,7 @@ jobs:
         run: |
           if [ -z "$DOCKERHUB_TOKEN" ]; then exit 0; fi
           docker buildx build \
+            --build-arg VERSION=${VERSION} \
             --push \
             --tag samiahmed7777/trianglesd:$VERSION \
             --tag samiahmed7777/trianglesd:latest \