Reads head camera from Isaac Sim shared memory, encodes as JPEG (quality 85),
and relays to Quest 3 over the existing WebSocket connection at ~15fps.
Falls back to left/right wrist cameras if head SHM unavailable.
Prevents Python resource_tracker from destroying SHM on bridge exit.
Also increases WebSocket write buffer and reduces send rate for stability.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>