Fix applybounds

Applybounds doesn't move client when it overlays
only with border with monitor to the right.

Apparently, c->geom.width already includes the border
as well.

feat: focus empty monitor when clicked

use round(3) and ceilf(3) from the math library

ΔSLOC: -1

set preferred scale after the first commit (XDGshell)

drop useless maplayersurfacenotify()

set O_NONBLOCK flag to stdout

add bugref about why we call updatemons in outputmgrapplyortest

set preferred scale on creation (LayerShell)

correctly report position to xwayland clients

Previously we didn't take into account their borders requiring us to add
`borderpx` to override_redirect clients.

Fixes: https://codeberg.org/dwl/dwl/issues/651

Reapply gamma LUT when re-enabling an output using wlr-output-power-management

Updated power management handling to address issues raised in the PR

Prevent updatemons() from removing monitors that have been put to sleep from the layout

Implement support for output power management

This patch is based on the original stale patch by Guido Cella @guidocella.
It has been modified to apply cleanly to the latest v5.0 tag. Since the SLOC
limit is now lifted, this core feature should be merged into dwl upstream.

Thanks to Dima Krasner @dimkr for the cherry-pick.

Closes: #559, #525

Check for null monitor in resize function

Add output to layout after enabled state is committed

fix: make sure selmon doesn't get set to disabled mon

Run startup_cmd in new session and kill the entire group

When a user's startup_cmd is a little more complex, e.g. a shell script,
and forks off several processes, then killing only the main child pid
might leave unwanted processes behind on exit. Not all children will
notice when their parent or the compositor has quit.

To fix this, put startup_cmd into its own session and process group, and
kill the entire group on exit.

Make sure toplevel_from_wlr_surface is called with a valid surface pointer

make sure clients share the same layer on floating layout

create a keyboard group for each virtual keyboard