Mirror of zebra-report 3ca9042 + proxy.unturf.com bc04362.
- moderation: boot failures now log to the moderator's page instead
of looking like the button did nothing (stale uuid case).
- diagnostic: watchFirstFrame fires 'still black after 2500ms — no
keyframe?' if a fresh SFU video tile never decodes a first frame.
- proxy-side companion: longer keyframe-burst on subscriber attach
so a dropped PLI no longer leaves the tile permanently black.