fix checking idle inhibit state

checking `bypass_surface_visibility` first, could cause that even if the idle
inhibitor is being destroyed it will disable idle tracking

and if we couldn't get its scene tree, then assume that the surface is visible

Revert "Revert "Check that inhibitor scene tree is not null""

This reverts commit 035bb99d67b59a84cfc2e911d222fb597591a8be.

Not checking `tree != NULL` result in a segfault if the surface doesn't have a
role (for example because it is a newly created surface)

Closes: https://github.com/djpohly/dwl/issues/359

get `sel` from focustop() in focusstack()

Fixes: https://github.com/djpohly/dwl/issues/354

Revert "force line-buffered stdout if stdout is not a tty"

This reverts commit deb48ff48b186ff77a7e9d3b3ab724ff4c3c340f.

Fixes: https://github.com/djpohly/dwl/issues/253

implement ext-session-lock-v1

Revert "remove unneeded changes in commitnotify()"

This reverts commit 30c24a53ad2aaa842bc3b028ba0b98e3362dad7c.

Bug: https://github.com/djpohly/dwl/issues/349

Revert "fix flickering when resizing/spawning windows"

This reverts commit 017bb7d7521f68d37bfe656c10f45edbcc92dd61.

Bug: https://github.com/djpohly/dwl/issues/349

return early if couldn't find the popup's parent

fix popups appearing outside the monitor

and a potentially crash

improve type safety of toplevel_from_wlr_surface()

merge toplevel_from_{wlr_layer_surface,popup} into client_from_wlr_surface

now it is a big function called toplevel_from_wlr_surface

remove unneeded call to wlr_scene_rect_set_color()

wlr_scene_rect_create() requires a color as parameter

add option for set button map

fix null deref in sigchld() if Xwayland is disabled

remove unneeded changes in commitnotify()

fix flickering when resizing/spawning windows

Fixes: https://github.com/djpohly/dwl/issues/306

use root surfaces to check idle inhibitors

References: https://github.com/djpohly/dwl/pull/343

Revert "Check that inhibitor scene tree is not null"

This reverts commit 9c155eefdc018f878ea6950e6bd383b985401339.

This commit was applied just a workaround, the proper fix is the next commit

Check that inhibitor scene tree is not null

unset fullscreen when mapping a client in the same monitor

Fixes: https://github.com/djpohly/dwl/issues/327