QOL improvement: ⌘-, should toggle Config display

As a quality-of-life improvement:

If you get very buried in a config (for example, **Settings → Keyboard → Custom Presses -> Add shortcut** while you have `showkeys` running), it’s annoying that you have to either entirely back out or tap outside the Config panel to dismiss it, and then if you find you need to tweak what you just set, you have to repeat the steps again.

Could I suggest that ⌘-, (command-comma) work as a _toggle_ of Config visibility? That way, if you want to test how the custom press works, you could add it, then hit ⌘-, and try it, then hit ⌘-, again and be back at the **Add shortcut** config rather than having to re-traverse the config hierarchy?

Tapping outside could do the same, or it could preserve the current behavior to be a way to exit and “rewind” the Config back to the top on next use.

Start by reproducing the flow through Settings → Keyboard → Custom Presses → Add shortcut while showkeys is running, then inspect the Config panel's handling of ⌘-, and dismissal by tapping outside. Done means ⌘-, hides and restores the current Config screen so the Add shortcut state is preserved, with the chosen outside-tap behavior documented or verified.

Written by the indexing model from the issue text.