feat: redesign hero section with cloud background and decorative blobs

- Replaced hero background image with cloud.png and added cyan gradient blobs for visual depth
- Centered hero content with larger typography and improved spacing
- Removed onGetStartedClick callback in favor of direct href navigation

src/components/Header.tsx

@@ -28,7 +28,7 @@ export function Header() {
   return (
     <header>
       <nav>
-                <Container className="relative z-50 flex justify-between py-4">
+                <Container className="relative z-50 flex bg-transparent justify-between py-4">
           <div className="relative z-10 flex items-center gap-16">
             <Link to="/" aria-label="Home">
               <img src={pmyceliumLogo} alt="Mycelium" className="h-8 w-auto" />