Fix i18next and backend loading by replacing node_modules references with CDN links

[ac-mmi]

This PR fixes a bug where i18next and i18next-http-backend were failing to load on GitHub Pages due to 404 Not Found errors.

Problem

• The current requirejs.config in js/loader.js points to ../node_modules/... for i18next and its backend.
• On GitHub Pages, the node_modules directory is not published, so these scripts cannot be loaded.

Solution

• Updated requirejs.config in js/loader.js to load i18next and i18next-http-backend directly from the jsDelivr CDN.
• This ensures the files are always available in both local development and GitHub Pages environments.

Benefits

• Fixes runtime errors (404 Not Found).
• Ensures i18n support works consistently in the hosted version of Music Blocks.
• No need to commit vendor files or ship node_modules in the repo.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[walterbender]

@ac-mmi doesn't this mean that you need to load over the internet under all circumstances? I am thinking of the scenario where you are running a local server, not connected to the net. Maybe we should try local and if it fails, revert to the remote files?

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[ac-mmi]

@walterbender I’ve updated loader.js to first try loading i18next and the backend from the local lib/ folder, and only fall back to the CDN if those aren’t available. This way it works both offline and online.