Add multi-disk copy workflow

ops/build-image.sh

@@ -21,6 +21,7 @@ ROOT_DIR=$(CDPATH= cd -- "$(dirname "$0")/.." && pwd)
 die() { echo "error: $*" >&2; exit 1; }
 
 command -v docker >/dev/null 2>&1 || die "docker not found in PATH"
+command -v go >/dev/null 2>&1 || die "go not found in PATH"
 
 DEFAULT_TAG=$(git -C "${ROOT_DIR}" rev-parse --short HEAD 2>/dev/null || echo dev)
 
@@ -46,6 +47,12 @@ else
     ask IMAGE     "Image" ""
 fi
 
+echo "checking Go build"
+(
+    cd "${ROOT_DIR}"
+    go build ./...
+)
+
 if [ -n "${IMAGE}" ]; then
     # multi-arch build + push
     docker buildx version >/dev/null 2>&1 || die "docker buildx not available"