Remove unused npm watch scripts

[julien-deramond]

Warning

Heavily draft

This PR follows up on #41574, which introduced automatic Sass recompilation for Astro.

The goal is to identify and remove watch* npm scripts that are no longer necessary.

Currently, these scripts are only triggered through the main watch script, which runs when executing npm run start. There are no known use cases where the watch-* scripts are run directly.

We'll evaluate them one by one.

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🟢 watch-js-docs

Steps:

1. Remove the watch-js-docs npm script.
2. Run npm run start.
3. Edit site/src/assets/stackblitz.js (e.g., change a comment in the HTML).
4. Confirm that Astro detects the change and recompiles automatically.
5. Click the “Try it on Stackblitz” button — the updated comment appears as expected.

Conclusion: watch-js-docs is no longer needed and can safely be removed.

🔴 watch-css-docs

Astro can recompile files like site/src/scss/_variables.scss on the fly (e.g., to update the $bd-purple Sass variable), but it doesn’t trigger the linter. That’s why we keep watch-css-docs running to execute npm run lint in real time.

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TODO

• watch-css-main
• watch-css-dist
• watch-css-test
• watch-js-main
• watch → watch-*
• start → watch

[julien-deramond]

Closing for now as we need more thoughts on this.
While removing watch-js-docs and other watch-* tasks could still "work", it would mean losing the automatic on-the-fly execution of npm *lint.

Additionally, Astro currently does not reload when files in dist/* change: so updates to component JS code are not hot-reloaded, and CSS changes in a component do not update the example pages (only the main docs).