tools/install.sh required node and npm and installed neither. Measured on a
snapshot-reverted Debian 13 image with no node, npm or git: the run stopped
at `require_cmd node` with "Required command not found: node", exit 1,
nothing installed, and no indication of how to proceed.
Adds ensure_node() to preflight. It fetches an official Node.js release into
$HOME/.mosaic/node, verifies it against that release's SHASUMS256.txt, and
refuses rather than degrades when the entry is missing or the checksum does
not match. sha256sum on Linux, shasum on macOS. .tar.gz over the smaller
.tar.xz because gzip is universally present and xz is not — a minimal image
is the case this exists to handle.
No-op when a suitable node is already on PATH, so it never fights an
operator's nvm/fnm/distro node. MOSAIC_SKIP_NODE_BOOTSTRAP=1 declines the
download and fails with instructions instead.
Inlined rather than factored into a sibling file because this script is
fetched standalone by curl and has nothing to source.
fred
cc0d24d5c4