feat: Racing Cards landing page - Astro + Tailwind v4

- Mobile-first dark mode landing
- Lucide icons (zero emojis)
- Self-hostable (Dockerfile + nginx)
- 10 card images generated with Nano Banana 2
- Sections: Hero, How It Works, Card Gallery, Features, Early Access, Footer
- Simple HTML form (no Netlify dependency)
- Zero JS output, static HTML

src/pages/index.astro

@@ -0,0 +1,22 @@
+---
+import Layout from '../layouts/Layout.astro';
+import Header from '../components/Header.astro';
+import Hero from '../components/Hero.astro';
+import HowItWorks from '../components/HowItWorks.astro';
+import CardGallery from '../components/CardGallery.astro';
+import Features from '../components/Features.astro';
+import EarlyAccess from '../components/EarlyAccess.astro';
+import Footer from '../components/Footer.astro';
+---
+
+<Layout>
+  <Header />
+  <main id="main-content">
+    <Hero />
+    <HowItWorks />
+    <CardGallery />
+    <Features />
+    <EarlyAccess />
+  </main>
+  <Footer />
+</Layout>