KBFS GUI issues under i3wm

Though it's not super pressing right now considering the GUI handles nothing the CLI/a shell can't already accomplish, I thought I'd go ahead and report it:

When attempting to open or interact with the KB(FS) GUI under i3wm (**edit:** specifically i3-gaps, where things are at least a bit more manageable thanks to the gaps), the window opens as a non-floating window. This isn't too big of an issue because of the window class assigned to all Keybase windows, so I just added `for_window [class="Keybase"] floating enable` to my i3 config, which made every window that opened a floating window (like a popup, for non-i3 users, as opposed to a tiling window). However, this causes issues as most floating windows are centered in the middle of the screen (or in the KBFS GUI's case, every other open is in the center, whereas every other time it's in the top right?), on top of all normal windows. And, because the GUI is typically used with a mouse **and** closes the window when focus is lost, it becomes impossible to move the mouse to the window without disabling `focus_follow_mouse`, a setting that I would like to keep.

I'm not sure if anything can be done about this, whether on my end or yours, but I thought I'd put it here anyway. Perhaps I should just leave it as a non-floating window, but that still leaves the focus issue, and causes ugly scaling issues with the UI.

The issue names no source file, entry point, or test. Start by reproducing the KBFS GUI behavior under i3 or i3-gaps with focus_follow_mouse enabled, comparing floating and non-floating windows; done would require an agreed fix or documented configuration guidance for the reported focus and placement problems.

Written by the indexing model from the issue text.