Add initial setup scripts for Debian 13 Trixie LUKS template

debian/13-trixie-luks/files/90-initial-login-setup.sh

@@ -0,0 +1,26 @@
+#! /bin/sed 2,5!d;s/^#.//
+# This script must be sourced from within a shell
+# and not executed. For instance with:
+#
+#   . /usr/local/bin/initial-setup.sh
+
+# Only run in interactive shells
+case $- in
+  *i*) ;;
+  *) return ;;
+esac
+
+if [ "$EUID" -ne 0 ]; then
+  if ! command -v sudo >/dev/null 2>&1 || ! sudo -n true >/dev/null 2>&1; then
+    echo "Error: must be root or have sudo privileges to run initial login setup." >&2
+    return
+  fi
+fi
+
+SENTINEL="/var/lib/initial-login-setup.done"
+
+if [ ! -f "$SENTINEL" ] && [ -x /usr/local/bin/initial-setup.sh ]; then
+  #DEBUG touch SENTINEL before running the setup script to prevent infinite loops during development
+  sudo /usr/local/bin/initial-setup.sh
+  sudo touch "$SENTINEL"
+fi