See swaywm/sway#5299 (comment)

Would it be possible to have Peek automatically start the render after capture, saving it using the default filepath it already uses?

Wayfire should have an option/way, to not overlap panel/dock upon window move

When wl-copy is sent a signal to terminate it, it should clean up the temp buffer files instead of leaving them around.

This is a very simple shell protocol only allowing for fullscreen surfaces. You can find a very basic implementation here: https://github.com/swaywm/wlroots/blob/master/examples/fullscreen-shell.c

To help new users get started it would be helpful to ship an example config which users could use to derive their own.