Alternative playground idea

_First of all, thank you for creating such a comprehensive resource and making it freely available! As I often get asked about where to start learning JS, this is constantly in my top 3-4 aswers :)_

I wonder, are you open to adding an alternative playground option if it would provide an improved experience for your users?

I'm thinking specifically about StackBlitz, some of the benefits being:
- no ads
- familiar editor UI, that a lot of people know from Visual Studio Code
- support for dark/light themes
- a possibility to render a Console right in the UI, which could optionally allow replacing `alert` with `console.log` for a non-blocking flow
- a possibility to add Node.js articles in the future, since StackBlitz supports it too (see e.g. https://node.new)

I've made a quick proof of concept of how the experience could look like:


Thanks again, and I'm curious to hear your thoughts!

Start with the issue body and its linked StackBlitz proof of concept. Assess whether an alternative playground should be integrated into the tutorial and define the affected articles, user experience, and acceptance criteria; the issue does not identify files, tests, or a concrete definition of done.

Written by the indexing model from the issue text.