feat(landing): glassmorphism visual upgrade with dark/light theme toggle
Comprehensive visual overhaul of the Atlas Landing Site:
- Dual-theme token system with light mode support via [data-theme="light"]
- Glassmorphism + glow effects across all components (blur, gradient borders, glow shadows)
- Theme toggle in navbar with localStorage persistence and system preference detection
- Hero section: aurora glow orbs, gradient headline, floating screenshot animation
- Animated gradient CTA buttons, glass card hover effects with gradient border reveal
- Stagger scroll reveal animations, noise texture overlay, section gradient backgrounds
- All 18 component files updated, no new files created
8116eee6c1