Create a universal ESM bundle for highlight.js

To ensure maintainability and compatibility with the Neo.mjs zero-builds dev mode, we must use a single version of highlight.js for both client-side and server-side rendering. The SSR process runs the exact same application code as the browser, so a single, universal module is required.

The stock npm package is CommonJS and not suitable for direct browser ESM import.

Plan

1. Create a build script (e.g., in buildScripts/) that uses the highlight.js build tools to generate a custom, universal bundle.
2. The script must output a single file in ESM format (e.g., highlight.custom.mjs).
3. This bundle must include only the languages required for the project: bash, css, javascript, json, scss, xml.
4. The generated file will be saved into the repository at resources/lib/highlight/highlight.custom.mjs.
5. This single, custom bundle will be the only version of highlight.js used across the entire platform (Node.js and browser), ensuring consistency and maintainability.

Implementation Details

We have successfully created a build script that generates a custom highlight.js bundle.

The original plan was to use the highlight.js build tools directly, but we discovered that the npm package does not include them.

Instead, we have implemented a build script that:

1. Clones the highlight.js repository from GitHub into a temporary directory.
2. Installs the dependencies.
3. Runs the highlight.js build script to generate a custom bundle with the required languages (bash, css, javascript, json, scss, xml).
4. Copies the generated bundle and a minified version to the dist/highlight directory.
5. The script is cross-platform compatible and is run automatically after npm install via a postinstall script. A manual build-highlightjs script is also available.

The generated files are placed in the dist/ folder and are not committed to the repository.