Add a complete light mode theme with a ThemeContext and CSS custom properties
for all UI surfaces. Replaces hardcoded dark colors with theme-aware
equivalents across 32 files including:
- Tailwind config extended with theme color tokens
- CSS custom properties for light/dark palettes in index.css
- ThemeContext provider in App.tsx with system preference detection
- All editor panels, dialogs, timeline, and settings updated to use
theme-aware classes (text-foreground, bg-surface, border-border, etc.)
- Timeline glass effects and module CSS updated for both modes
- UI primitives (accordion, switch, slider, sonner) themed
webadderall