feat: Refactor Events Page to Card-Based Grid Layout

What changed

Refactored the Events page from a single-event hero layout to a reusable card-based grid layout with an EventCard component.

Why

The previous layout only supported one event hardcoded in a hero format. This change makes it scalable — new events can be added from the backend without any frontend changes.

Before

After

Checklist

• EventCard component created and reusable

• Existing event migrated to card format

• Responsive layout works (1 col mobile → 3 col desktop)

• Hover states working

• Brand colors maintained

• No breaking changes to other pages

  closed #48 (closed)