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.

scripts/post-install.sh

@@ -15,10 +15,7 @@ check_pacman
 
 if ! command -v paru &>/dev/null; then
     log "Installing paru..."
-    PARU_TMPDIR=$(mktemp -d)
-    git clone https://aur.archlinux.org/paru.git "$PARU_TMPDIR/paru"
-    (cd "$PARU_TMPDIR/paru" && makepkg -si --noconfirm)
-    rm -rf "$PARU_TMPDIR"
+    sudo pacman -S --needed --noconfirm paru
 else
     log "paru already installed."
 fi
@@ -111,7 +108,7 @@ USER_SERVICES=(
 )
 
 for service in "${USER_SERVICES[@]}"; do
-    if systemctl --user list-unit-files "${service}.service" &>/dev/null; then
+    if systemctl --user cat "${service}.service" &>/dev/null; then
         systemctl --user enable "$service"
         log "  + $service (user)"
     else

scripts/transform.sh

@@ -194,10 +194,7 @@ fi
 # Install paru if not present
 if ! command -v paru &>/dev/null; then
     log "Installing paru..."
-    PARU_TMPDIR=$(mktemp -d)
-    git clone https://aur.archlinux.org/paru.git "$PARU_TMPDIR/paru"
-    (cd "$PARU_TMPDIR/paru" && makepkg -si --noconfirm)
-    rm -rf "$PARU_TMPDIR"
+    sudo pacman -S --needed --noconfirm paru
 else
     log "paru already installed."
 fi
@@ -300,7 +297,7 @@ USER_SERVICES=(
 )
 
 for service in "${USER_SERVICES[@]}"; do
-    if systemctl --user list-unit-files "${service}.service" &>/dev/null; then
+    if systemctl --user cat "${service}.service" &>/dev/null; then
         systemctl --user enable "$service"
         log "  + $service (user)"
     else