Ship a Node entry in the npm package #2

The npm package ships only the browser files (dist/). Programs and test suites that want to run Java under Node have to use a source checkout: src/node.ts exports runNode and the CLI, but it runs as TypeScript and reads the exploded build/jdk image that pnpm jdk builds.

Proposal: ship a built Node entry in the package, for example dist/node.js exporting runNode, plus a bin, that runs on Node 23.6 or newer against the packaged dist/boot.pack and dist/jdk/<module>.jar files instead of build/jdk.

Open questions:

• Reading classes and resources from the per-module jars on disk, as the browser does over HTTP, instead of the exploded image.
• Which runNode options are public API.
• Package size: the Node entry adds little, since it reuses the same jdk/ files.