Add cmd_verify prompt to install output; fix --insecure docs

- install.sh: print 'verify' command immediately after successful restart
  so users know to confirm the backend patch loaded before creating tasks
- README: correct --insecure description; it controls TLS to the TrueNAS
  API (where the API key is transmitted), not the S3 endpoint — previous
  wording implied it was safe to use for S3 self-signed certs

install.sh

@@ -117,6 +117,9 @@ if ! systemctl restart middlewared; then
 fi
 echo "Done."
 echo ""
+echo "Verify the backend patch loaded correctly:"
+echo "  python3 $PATCH_DIR/create_task.py verify"
+echo ""
 echo "Refresh your browser to pick up the UI change."
 echo ""
 echo "To create a TrueCloud Backup task with S3 or B2 credentials:"