Improve placement of "Toggle Details" button in narrow contexts

[jeffdaley]

This fella:

Is your feature request related to a problem? Please describe.
The button floats into the gutter of the main panel which causes issues in narrow window contexts, in some case putting it out of view:

It also causes some unwanted UI overlap :

CleanShot.2025-01-10.at.11.47.18.mp4

I would like a persistent button for this control, or the ability to toggle the pane by some other persistent control.

Here's a quick idea: