Add moonarch-git and sweet-cursors-git PKGBUILDs

moonarch-git packages all desktop environment defaults (XDG configs,
helper scripts, zsh config, wallpaper) for pacman-managed deployment.
Includes moonarch-update for simplified system maintenance.

sweet-cursors-git packages the Sweet cursor theme separately.

moonarch-git/moonarch.install

@@ -0,0 +1,34 @@
+# ABOUTME: Post-install hooks for moonarch-git package.
+# ABOUTME: Handles zsh integration and configs owned by other packages.
+
+post_install() {
+    # Zsh integration: source moonarch defaults for users without ~/.zshrc
+    if ! grep -q "zshrc.moonarch" /etc/zsh/zshrc 2>/dev/null; then
+        echo '# Moonarch defaults (overridden by ~/.zshrc)' >> /etc/zsh/zshrc
+        echo '[[ ! -f "$HOME/.zshrc" ]] && source /etc/zsh/zshrc.moonarch' >> /etc/zsh/zshrc
+    fi
+
+    # Deploy greetd config (file owned by greetd package, overwrite deliberately)
+    if [ -d /etc/greetd ]; then
+        cp /usr/share/moonarch/greetd/config.toml /etc/greetd/config.toml
+        cp /usr/share/moonarch/greetd/niri-greeter.kdl /etc/greetd/niri-greeter.kdl
+    fi
+
+    # Deploy moongreet config (file owned by moongreet-git, overwrite deliberately)
+    if [ -d /etc/moongreet ]; then
+        cp /usr/share/moonarch/moongreet/moongreet.toml /etc/moongreet/moongreet.toml
+    fi
+
+    # Cleanup legacy /usr/local/bin/ scripts from pre-package installs
+    rm -f /usr/local/bin/moonarch-* 2>/dev/null || true
+    rm -f /usr/local/bin/swww /usr/local/bin/swww-daemon 2>/dev/null || true
+    rm -f /usr/local/bin/moonarch-update 2>/dev/null || true
+
+    echo "==> Moonarch defaults installed."
+    echo "==> For first-time setup run: /opt/moonarch/scripts/post-install.sh"
+    echo "==> This enables services, configures firewall, and sets up user defaults."
+}
+
+post_upgrade() {
+    post_install
+}