Masscan finds are rtsp:// with no snapshot_url, so the popup skipped the
<img> and the leftover source link handed the OS an rtsp:// URL (VLC).
- Popup always hits /api/cameras/{id}/snapshot (HTTP stills, then one
ffmpeg frame grab). No credentials. 10s hard timeout.
- rtsp:// is rendered as text, never as an href.
- ffmpeg added to the app image for the RTSP still/MJPEG path.
- Default MASSCAN_RATE 200 (1k/10k saturated the home uplink).
