Wake internal display only when leaving clamshell

The clamshell watcher polls omarchy-hyprland-monitor-clamshell every two
seconds and calls enable_internal unconditionally which re-enabled DPMS
on the internal panel each time. When the lock screen blanks the displays,
the next poll of  omarchy-hyprland-monitor-clamshell re-lights the laptop
screen, leaving it showing the lock screen indefinitely while external
monitors stayed off.

Only issue the DPMS wake when the clamshell flag was actually consumed,
i.e. on the lid-open transition the wake was meant for.

If the lid-open even fails to turn on the screen for whatever reason,
then pressing a key or moving the mouse will re-light the screen. This
is configured in `input.lua` via `key_press_enables_dpms = true` and
`mouse_move_enables_dpms = true`

bin/omarchy-hyprland-monitor-clamshell

@@ -115,7 +115,10 @@ enable_internal() {
 
   [[ -f $MANUAL_DISABLE_FLAG ]] && omarchy-hyprland-monitor-external-active && return 0
   sync_internal_scale
-  dpms_internal enable
+
+  if (( changed )); then
+    dpms_internal enable
+  fi
 }
 
 disable_internal() {