fix: PKGBUILD compositor-agnostisch, Beispiel-Configs bereinigt

Moongreet ist ein reiner GTK4-Greeter ohne eigenen Compositor.
niri-greeter.kdl entfernt — der User konfiguriert seinen
Compositor selbst (regreet → moongreet tauschen).

pkg/moongreet.install

@@ -1,16 +1,14 @@
 # ABOUTME: pacman install hooks for Moongreet.
-# ABOUTME: Sets ownership on cache directory for the greeter user.
+# ABOUTME: Sets ownership on cache directory and prints setup instructions.
 
 post_install() {
     if getent passwd greeter > /dev/null 2>&1; then
         chown greeter:greeter /var/cache/moongreet
     fi
 
-    echo "==> Copy /etc/moongreet/moongreet.toml and adjust the wallpaper path."
-    echo "==> Configure greetd to use moongreet:"
-    echo "    [default_session]"
-    echo "    command = \"moongreet\""
-    echo "    user = \"greeter\""
+    echo "==> Moongreet installed."
+    echo "==> Add moongreet to your greeter compositor command in /etc/greetd/config.toml."
+    echo "==> Adjust wallpaper: /etc/moongreet/moongreet.toml"
 }
 
 post_upgrade() {