Add helper script templates and align reference guidance.

Point helper-script generation at shared templates, tighten prefix-based Quadlet handling, and refresh the bundled Quadlet reference formatting.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

references/template/reload_template.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+set -eu
+
+# Reload systemd after reviewed Quadlet unit changes.
+# Update the systemctl_cmd() function below before using this template.
+
+systemctl_cmd() {
+	systemctl --user "$@"
+}
+
+systemctl_cmd daemon-reload