Add 9router start-on-boot setup (non-root, @reboot cron, no systemd)

start-9router.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+# Start 9router detached at boot.
+# Runs as the current user; if that's root, drop privileges to 'ardhi'.
+# Uses absolute paths (cron @reboot has a minimal PATH).
+
+SETSID=/usr/bin/setsid
+RUNUSER=/usr/sbin/runuser
+BIN=/usr/local/bin/9router
+LOG=/home/ardhi/9router.log
+
+touch /tmp/9router-cron-ran 2>/dev/null
+
+if [ ! -x "$BIN" ]; then
+  exit 0
+fi
+
+if [ "$(id -u)" = "0" ]; then
+  # Running as root (e.g. root's @reboot cron): drop to ardhi.
+  "$SETSID" "$RUNUSER" -u ardhi -- sh -c \
+    "exec '$BIN' -t -n --host 127.0.0.1 --port 20128 >> '$LOG' 2>&1 < /dev/null" &
+else
+  # Already running as ardhi: start directly.
+  "$SETSID" "$BIN" -t -n --host 127.0.0.1 --port 20128 >> "$LOG" 2>&1 < /dev/null &
+fi
+disown 2>/dev/null || true
+exit 0