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/install_template.sh

@@ -0,0 +1,29 @@
+#!/bin/sh
+set -eu
+
+# Copy reviewed Quadlet unit files into the target Quadlet directory.
+# Update the variables below before using this template.
+
+SCRIPT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
+QUADLET_PREFIX='app-'
+QUADLET_TARGET_DIR="${HOME}/.config/containers/systemd"
+
+list_quadlet_files() {
+	for ext in container pod network volume build image kube; do
+		for file in "$SCRIPT_DIR"/"$QUADLET_PREFIX"*."$ext"; do
+			[ -e "$file" ] || continue
+			printf '%s\n' "$file"
+		done
+	done | LC_ALL=C sort -u
+}
+
+files=$(list_quadlet_files)
+[ -n "$files" ] || {
+	printf 'No Quadlet files found for prefix %s\n' "$QUADLET_PREFIX" >&2
+	exit 1
+}
+
+mkdir -p -- "$QUADLET_TARGET_DIR"
+printf '%s\n' "$files" | while IFS= read -r file; do
+	install -m 0644 -- "$file" "$QUADLET_TARGET_DIR/$(basename -- "$file")"
+done