fix: wordmark optical weight — UI font + balanced gradient (#32)

Switch wordmark from monospace to system UI font: monospace fonts pack three strokes into 'm' at display sizes, making it read lighter than single-stroke neighbors. UI fonts are optically balanced for large weights.

Change gradient from 135deg blue→purple to 90deg (horizontal) across a tighter perceptual range (#6ea8fe → #a78bfa → #c084fc) so all four letters sit at similar luminosity on a dark background.

Scale 'Version Anything' subtitle down slightly and increase letter-spacing from 2px to 4px for better proportion against the larger wordmark.

Co-authored-by: Gabriel Cardona <gabriel@tellurstori.com>