feat: animated hero with parallax rocket + scroll reveal animations

- Add animated hero section with parallax rocket SVG that descends on scroll
- Add floating decorative particles and gradient layers in hero
- Add staggered text reveal animation on hero h1
- Create ScrollReveal component (IntersectionObserver-based fade/slide)
- Create AnimatedCounter component for stat numbers
- Add scroll animations to all sections (Problematique, System, Demos, AboutMe, FAQ, Contact, Footer)
- Add smooth FAQ accordion transitions
- Add extensive CSS keyframe animations (float, flame, particles, stat glow)

https://claude.ai/code/session_01V8YAjpqRQ3bfBYsABYsEgo

components/animations/FloatingElements.tsx

@@ -0,0 +1,20 @@
+"use client";
+
+export default function FloatingElements() {
+  return (
+    <div className="absolute inset-0 overflow-hidden pointer-events-none">
+      {/* Particules flottantes */}
+      <div className="absolute top-1/4 left-[10%] w-2 h-2 bg-orange/20 rounded-full animate-float-slow" />
+      <div className="absolute top-1/3 left-[25%] w-3 h-3 bg-white/5 rounded-full animate-float-medium" />
+      <div className="absolute top-1/2 left-[70%] w-2.5 h-2.5 bg-orange/15 rounded-full animate-float-fast" />
+      <div className="absolute top-[20%] left-[80%] w-1.5 h-1.5 bg-white/10 rounded-full animate-float-slow" />
+      <div className="absolute top-[60%] left-[15%] w-2 h-2 bg-orange/10 rounded-full animate-float-medium" />
+      <div className="absolute top-[70%] left-[50%] w-1 h-1 bg-white/15 rounded-full animate-float-fast" />
+
+      {/* Cercles décoratifs */}
+      <div className="absolute -top-20 -right-20 w-80 h-80 border border-white/5 rounded-full" />
+      <div className="absolute -bottom-32 -left-32 w-96 h-96 border border-orange/5 rounded-full" />
+      <div className="absolute top-1/4 right-[30%] w-48 h-48 border border-white/3 rounded-full" />
+    </div>
+  );
+}