The dashboard pins engines node >=24.14.1 with engine-strict, so make
bootstrap dies with EBADENGINE on any shell whose default node is older.
Wrap the npm install in scripts/with_dashboard_node.sh: it execs the
command as-is when node already meets the floor, otherwise activates the
.nvmrc version via nvm or fnm, and fails fast with install instructions
when neither manager exists