fix(nav): show floating nav whenever scrolled past hero

Previous logic required scrolling UP past 80px to reveal the nav,
which felt delayed. Show as soon as the user scrolls past the
threshold in either direction.

Author: 5oran9

components/site/floating-nav.tsx

@@ -25,14 +25,7 @@ export function FloatingNav() {
   const [visible, setVisible] = useState(false);
 
   useMotionValueEvent(scrollY, "change", (current) => {
-    const previous = scrollY.getPrevious() ?? 0;
-    if (current < 80) {
-      setVisible(false);
-    } else if (current < previous) {
-      setVisible(true);
-    } else {
-      setVisible(false);
-    }
+    setVisible(current >= 80);
   });
 
   return (