This follows the same patterns that Wallpaper and Bar did and makes
TagOverlay use the same manage/render cycle as the rest of the WM.
We also switched to just use a poll timer like river-tag-overlay instead
of using the timerfd. I realized that the Zig stdlib doesn't actually
support timerfds for FreeBSD right now and I don't feel like adding them.
We had to fix a couple of compile errors that weren't showing while it
wasn't wired up (since I never just tried to compile TagOverlay.zig on
its own). We also changed the lifecycle to re-create/destroy the surface
to show/hide it, similar to the way that river-tag-overlay actually did
it.
Finally, I added @branchHint(.cold) to a few places in the event loop
where, if we're in the branch, the wm is definitely exiting, so it's
fine if they're cold (should almost never happen).
This implements more of the text rendering and a clock was the easiest
part. I still need to add the tag bit. I'd also like to hide the tags
but still show the clock like beanclock when windows are fullscreened
This actually renders a wallpaper for each output using the newly added
Buffer and BufferPool for shared-memory surfaces and creates a
wlr-layer-shell surface per output. Right now, each wallpaper
shares the same wallpaper (though scaled to each).
wl_output globals get added to a HashMap that is used by Output when it
gets an output event.
Fix null-safety in WindowManager when no seats/outputs exist and route
Window dimensions through pending_manage.
