Designed to be used on a phone after scanning a QR code from the desktop. Shows a full-screen camera preview with minimal controls (flip camera + disconnect). Audio is always muted on the ghost participant.
A hidden <video id="local-video"> element is always rendered so the RTC
client can attach its transport stream. The visible video shows the preview
(before connecting) or the RTC-managed stream (after connecting).
Minimal, mobile-optimized page for joining a room as a video-only participant.