This commit implements the replay feature that allows users to pause the
live 3D view, scrub through a 48-hour recording buffer, and replay the 3D
scene exactly as it was at any historical moment.
Key components:
- Recording buffer with SeekToTimestamp for time-travel navigation
- Replay engine with session management (start, stop, seek, play, pause)
- Replay signal processing pipeline with tunable parameters
- REST API endpoints for replay control
- Dashboard UI with timeline scrubber, playback controls, and tuning panel
- Comprehensive test coverage for all replay functionality
Acceptance criteria met:
- Seek to any point in 48-hour window completes in < 1 second
- Replay produces identical blob positions to original live processing
- Parameter sliders re-process in < 3 seconds
- "Apply to Live" correctly writes parameter changes
- Timeline scrubber event markers correctly align
- "Back to Live" correctly resumes live detection
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
