Fix audit findings, replace wlogout with moonset

Bug fixes from quality and security audits:
- moonarch-capsnote: use value[0] instead of value[2]
- moonarch-btnote: guard empty PER_INT before integer comparison
- moonarch-clipboard + niri config: use XDG_RUNTIME_DIR instead of UID 1000
- moonarch-waybar-hidpp: use charging icon when charging
- moonarch-waybar-gpustat: find gpu_busy_percent dynamically across hwmon*
- post-install/transform: use systemctl --user cat for service detection
- post-install/transform: install paru from [extra] instead of AUR clone

Replace wlogout with moonset in niri keybind and waybar on-click.
Remove moonarch-session (dead code, replaced by moonset) and wlogout
layout config.

defaults/bin/moonarch-waybar-hidpp

@@ -28,7 +28,7 @@ for dev in /sys/class/power_supply/hidpp_battery_*; do
         fi
 
         if [ "$status" = "Charging" ]; then
-            text="${capacity}% 󰌌"
+            text="${capacity}% 󰂄"
         else
             text="${capacity}% 󰌌"
         fi