feat: improve color contrast for better readability ...

- Hero scroll indicator: changed from primary/70 to white (better contrast)
- Contact section tagline: increased opacity on text
- About section: body text changed from muted to white/90 (much clearer)
- Footer links: text-muted -> white/80
- Footer tagline: text-muted/60 -> white/70
- All elements now have better visibility against dark background

feat: enhance UI with logo support and improved design ...

- Updated globals.css with enhanced animations and glassmorphism
- Added Footer component with subtle gradient and links
- Enhanced Hero with logo display (fallback to text if missing)
- Improved About section with icons and better typography
- Enhanced Contact with larger CTA button and hover effects
- Added placeholder logo file (geekbrain-io.png)
- Improved scroll reveal animations with cubic-bezier timing
- Added bonce-slow animation for scroll indicator

Interface now looks much more polished and professional.

Co-Authored-By: Claude Opus 4.6 <[email protected]>