Redesign landing page based on Figma mockup

- Dark navy theme with sticky top nav bar
- Pain points as 3 colored icon cards instead of inline text
- Dashboard and Discord demo sections with captions
- 6 feature tiles in 2x3 grid with colored icons
- Proper footer with logo and nav links
- Responsive layout for mobile
- All SEO meta tags and Schema.org markup preserved

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: weiyong1024