Support Python libraries that generate HTML w/ JS

[wwwillchen]

Even with me.html and #95, there's still a gap in terms of supporting Python libraries which generate HTML+JS+CSS. Because we sanitize HTML inside me.html and custom web components requires the JS to be available ahead of time, I'm not sure yet what's the best way to address this.

If this is an unusual case, it may be worth asking libraries to provide a pre-generated HTML/JS/CSS and wrap it in a web component.

Examples:

• https://github.com/callummcdougall/sae_visualizer?tab=readme-ov-file / https://github.com/callummcdougall/sae_vis

[wwwillchen]

This can be addressed by part #2 of #156 (sandboxed html)