feat(video): scale all elements to 2x for 4K output

- Composition: 1920x1080 → 3840x2160
- All font sizes, spacing, border radii, padths, and element dimensions doubled
- Grid background size: 60px → 120px
- slideUp default distance: 40px → 80px
- Fix license text: MIT → Apache 2.0

Author: luongnv89