Same pattern as enable-udp-punch / enable-ipv6-punch: empty value reads
as on against the public server and off against a private one (the
injection lives in rustdesk's get_local_option), so self-hosted
deployments opt in once their server / TURN is ready.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ExUfAkYbq8UC9pQCiLy8TQ