Yup, I have a long been a fan of the notion panel-slide-in design.
I looked at getting something going in a theme component, but unfortunately a topic page is rather complex and not so easily slotted in elsewhere.
I have been thinking about displaying a trimmed down version of the topic (no timeline or summary for example) as a sort of quick preview, with the option to click through to get the full functionality.
We already have a 3 panel layout when using chat threads in full page, and I don’t think that’s too noisy, so from a design perspective I see this work really well.