refactor: extract hero content from aurora background component

- Separated HomeAurora into pure background component and new HomeHero for content
- Converted aurora to absolute positioned background layer in Layout for homepage
- Removed z-index conflicts and cleaned up background color declarations

src/pages/home/HomeHero.tsx

@@ -0,0 +1,28 @@
+import { Button } from '@/components/Button'
+
+export function HomeHero() {
+  return (
+    <div className="mx-auto max-w-7xl px-6 pt-20 pb-24 lg:pb-32 lg:px-8 lg:py-40">
+      <div className="mx-auto max-w-2xl text-center">
+        <h1 className="text-6xl font-semibold tracking-tight text-gray-900 lg:text-8xl">
+          The Sovereign Agentic Cloud
+        </h1>
+
+        <p className="mt-8 text-lg font-medium text-pretty text-gray-500 lg:text-xl/8">
+          Host nodes, deploy workloads, or build private AI systems,
+          all on infrastructure you own and control.
+        </p>
+
+        <div className="mt-10 flex items-center justify-center gap-x-6">
+          <Button variant="solid" color="cyan" href="#">
+            Start Hosting
+          </Button>
+
+          <Button href="#" variant="outline" color="gray">
+            Deploy in Cloud <span aria-hidden="true">→</span>
+          </Button>
+        </div>
+      </div>
+    </div>
+  )
+}