In source-build, don't build node/npm components - instead reference the minified .js files from the submodule
Error whenever the files in the submodule don't match what's in the repo
In any PR that would change the contents of the minified .js files, push the updated files to the submodule repo & ingest it in that same PR (so that we are testing changes here at the source, in the same way we would for full .NET source build)
Plan of record to fix the NPM build for source-build in .NET 9:
CC @javiercn @dotnet/source-build-contrib