fix: fall back to scp if rsync not available on builder VM

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/run-builder.sh

@@ -56,10 +56,16 @@ echo ""
 echo "=== downloading ISO ==="
 LOCAL_ISO_DIR="${REPO_ROOT}/iso/out"
 mkdir -p "${LOCAL_ISO_DIR}"
-rsync -az --progress \
+if command -v rsync >/dev/null 2>&1 && ssh -o StrictHostKeyChecking=no root@"${BUILDER_HOST}" command -v rsync >/dev/null 2>&1; then
+    rsync -az --progress \
         -e "ssh -o StrictHostKeyChecking=no" \
         "root@${BUILDER_HOST}:/root/bee/dist/*.iso" \
         "${LOCAL_ISO_DIR}/"
+else
+    scp -o StrictHostKeyChecking=no \
+        "root@${BUILDER_HOST}:/root/bee/dist/*.iso" \
+        "${LOCAL_ISO_DIR}/"
+fi
 echo ""
 echo "=== build complete ==="
 echo "ISO saved to: ${LOCAL_ISO_DIR}/"