production docker deployment update

docker/karung_sync_loop.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+# Sub-minute karung sync — cron cannot schedule under 1 minute.
+# Only started when KARUNG_WEB_ADMIN_SYNC_ENABLED=true (off by default at HQ).
+set -eu
+cd /app
+while true; do
+  /usr/local/bin/python manage.py sync_karung_from_web_admin >> /var/log/cron.log 2>&1 || true
+  sleep 30
+done