ONNX inference on ARM64 CPU takes ~750ms/frame, causing the detect
stream to fall behind at 5 FPS. This caps detection at 2 FPS to prevent
recording segment backlog and ffmpeg watchdog restarts. Also syncs
motion masks, zone coordinates, and alert labels from the live config.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>