Add XWayland support (#16)

* save dev state

* fix xwayland-satellite supervisor lifecycle, readiness and cleanup

* remove wayland scanner protocol generated files

* default xwayland enabled with path

* remove jargons

* address x11 review: park unconfirmed cleanup, never signal a reaped group, fix storm test and notify dir mode

* fix resize tests: never build Size values from negative dimensions

* add min-width/min-height window rules that replace client minimum sizes

* rename effective_size_constraints to effective_minimum_size and minor cleanups

packaging/config.kdl

@@ -15,6 +15,12 @@ commands {
     mic-mute "wpctl" "set-mute" "@DEFAULT_AUDIO_SOURCE@" "toggle"
 }
 
+xwayland {
+    enabled #true
+    startup on-demand
+    path "xwayland-satellite"
+}
+
 // These supplement the built-in shortcuts listed in docs/shortcuts.md.
 binding "Super+B" "spawn" "browser"
 binding "Super+Z" "spawn" "editor"