Task 5: Build FloatingNav component with active section tracking

- Created useActiveSection hook using IntersectionObserver for scroll tracking
- Built FloatingNav with Framer Motion animated indicator dot
- Added section IDs to App.tsx for scroll targets
- Added scrollbar-hide utility and smooth scroll to index.css

src/index.css

@@ -65,3 +65,16 @@ body {
 .animate-seed-pulse {
   animation: seedPulse 0.6s ease-in-out infinite;
 }
+
+.scrollbar-hide {
+  -ms-overflow-style: none;
+  scrollbar-width: none;
+}
+
+.scrollbar-hide::-webkit-scrollbar {
+  display: none;
+}
+
+html {
+  scroll-behavior: smooth;
+}