Conditionally show/hide Sidebery for windows that are taller than they are wide

[FFdhorkin]

Description

I have two monitors; one is oriented vertically, the other landscape (like most people).

Sidebery is great when I'm on my normal 16:9 monitor. But when I'm on my 9:16 monitor, vertical tabs take up critical screen real estate.

There's an addon I use called Paxmod that allows you to have multiple tab rows at the top of your screen.

I created a request over there to add ability to conditionally switch behavior. numirias/paxmod#108

I'm not sure whether some of this functionality would be better suited for implementation in Sidebery as opposed to Paxmod, so I'm creating a semi-duplicate issue here of the one there.

For convenience, here's a simplified version of my desired behavior that doesn't explain Sidebery behavior:

When I'm on my Portrait monitor:

• automatically close Sidebery if open (but leave other sidebars open)
• normal Paxmod behavior (titlebar disabled, multiple tab rows)
• integrate Sidebery panels into Paxmod so that I can access Sidebery panels even when Sidebery's sidebar is closed (not sure whether or not Sidebery exposes an API for the panels. I imagine the visual side of this would need to be on Paxmod side)

When I'm on my Landscape monitor:

• I would like to automatically open Sidebery sidebar
• replace Paxmod's tab rows with a combination of the default Firefox titlebar (i.e. your window title plus minimize/maximize/close buttons) and "tabs" that are actually Sideberry "panels" (basically, show what Sidebery shows at the top of their sidebar as the tabs at the top of the screen)

Current behavior / Example of why I want this:

[mbnuqw]

Impossible to do from Sidebery side. You can use #214 (Sidebery settings > General > Add preface...) with userChrome.css as a workaround (to show/hide native tabs when Sidebery sidebar is off/on), but Firefox still requires explicit user action (click) to open/close sidebar.