CONTRIBUTING.md said "Only a couple (`qa:map-source-tray`, `qa:transit`) have
an `npm run` alias". package.json defines five: `qa:map-source-tray`,
`qa:panel-resize`, `qa:street-level`, `qa:street-level:fixtures` and
`qa:transit`.
The two missing names are not incidental -- .github/workflows/ci.yml already
invokes `npm run qa:street-level:fixtures` and `npm run qa:panel-resize`, so a
contributor reading the guide is told to reach for `node scripts/<gate>.mjs`
for gates the project itself runs through npm.
Verified against package.json scripts and .github/workflows/ci.yml on main
(1df2a27).
