feat: design system v2 with liquid glass aesthetic
Overhaul design constants for OLED-first dark mode:
- Colors: brand palette, phase colors, glass/shadow tokens, gradients
- Typography: Inter font scale matching iOS type system
- Spacing: 4px base unit with layout constants
- Border radius: liquid glass card radii
- Animations: spring/timing presets for UI transitions
Add v2 product docs (PRD, PDD, BDSD) and update CLAUDE.md.
Install expo-video, expo-sharing, @expo-google-fonts/inter.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
511e207762