React/ReactDOM/Babel were loaded from the unpkg CDN at runtime — react@18
and react-dom@18 weren't even exact-pinned, and none had SRI. A CDN swap (or
react auto-resolving a new 18.x) could blank the whole app with no change on
our side: exactly the v78/v79 blank-screen class. It also made the self-hosted
box depend on outbound internet to render.
Vendor the three libs into frontend/assets/vendor/ (React 18.3.1, ReactDOM
18.3.1, @babel/standalone 7.29.7) and load them same-origin with sha384
integrity attributes. They now ship inside the s9pk (Dockerfile already COPYs
frontend/; server.py serves /assets/* with the path-containment check), so a
CDN can never swap prod deps again and no outbound fetch is needed at runtime.
Add start9/0.4/render-smoke.mjs: a jsdom render smoke check that (1) runs the
shipped Babel over the app's inline JSX and asserts a classic, non-module,
parseable script (the v79 ESM-import regression), and (2) mounts the app in
jsdom and asserts the login UI renders (the v78 blank-screen class). Wired into
the default `make` goal so every package build is gated on the frontend
actually rendering — closing the "verified live via curl only" gap. jsdom is a
build-time devDependency, not shipped in the image.
Keysat