v22 was created by restoring v19

Now I'll rewrite the activity-web component with a clean mobile-first vertical card stack design that runs once when scrolled into view, no SVG spider web.

The activity section now uses a clean mobile-first vertical card stack instead of the problematic SVG spider web. When the section scrolls 30% into view, the heading is already visible and the six activity cards animate in one-by-one with a fade + slight translate-up + scale-from-0.96 effect, staggered 120ms apart. The design matches the site aesthetic with glassmorphism cards, soft borders, subtle shadows, and a faint vertical guide line running through the center. Reduced motion preference is respected by showing all cards immediately without animation.