GHSA-25gx-x37c-7pph: OpenClaw's andbox browser noVNC observer lacked VNC authentication

The sandbox browser entrypoint launched x11vnc without authentication (-nopw) for noVNC observer sessions.

OpenClaw-managed runtime flow publishes the noVNC port to host loopback only (127.0.0.1), so default exposure is local to the host unless operators explicitly expose the port more broadly (or run the image standalone with broad port publishing).