Core Principle: Frame is the only standard
Changes:
- VideoPlayer: Add startFrame/endFrame props
- VideoPlayer: Use frame parameters in simple playback path
- SearchView: Remove frame/time conversion (stop using fps = 24)
- PeopleView: Pass frames directly instead of time
- PersonDetailView: Pass frames directly instead of time
All video streams now use startFrame/endFrame API parameters.
Time conversion only happens in VideoPlayer internals for UI display.
Ref: frame-based positioning standards research