UXP Caption Track Editing APIs

Building production UXP panels at a broadcaster to restyle broadcast → online sequences (different caption styles).

Issue: UXP can access CaptionTrack objects but lacks APIs to:
- Edit caption track styles  
- Copy/move caption track items between tracks
- Modify caption item properties

Impact: Cannot automate caption workflow despite full video track/MOGRT support existing.

Request: Add UXP APIs for:
1. CaptionTrack.setStyle() or applyTrackStyle()
2. Caption track item copy/move between tracks  
3. Caption item property editing (similar to ComponentParam for MOGRTs)

Caption-heavy newsroom workflows cannot be automated without these APIs.

Thanks for considering!