feat: Feature 3.1 — Landing page + blog + Phase 3 specs

Next.js 14+ web app in web/ directory:
- Landing page: Hero, How It Works, Features, 3-tier Pricing with
  founder badges, Footer with email capture
- Blog system: MDX-powered, /blog index + /blog/[slug] pages,
  reading time, Open Graph tags, JSON-LD structured data
- Auth pages: /login + /signup (Supabase Auth ready)
- Design system: dark theme, grade colors (A/B/C/D), BetonBLK voice
- 1 seed blog post: "How to Read Line Movement Like a Sharp"
- Specs for 3.2 (Scan UI), 3.3 (Bet Tracker), 3.4 (Stripe)

Build passes clean: 7 static pages generated.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/src/components/Hero.tsx

@@ -0,0 +1,22 @@
+export default function Hero() {
+  return (
+    <section className="relative min-h-[85vh] flex items-center justify-center px-4">
+      <div className="max-w-3xl text-center">
+        <h1 className="text-5xl md:text-7xl font-bold tracking-tight mb-6">
+          Stop guessing.<br />
+          <span className="text-[var(--accent)]">Start grading.</span>
+        </h1>
+        <p className="text-lg md:text-xl text-[var(--text-muted)] mb-10 max-w-xl mx-auto">
+          BetonBLK scans your parlay in seconds. AI-powered prop analysis across DraftKings, FanDuel, and BetMGM.
+        </p>
+        <a
+          href="/scan"
+          className="inline-block px-8 py-4 bg-[var(--accent)] text-white font-semibold rounded-xl text-lg hover:opacity-90 transition"
+        >
+          Scan Your First Parlay — Free
+        </a>
+        <p className="mt-4 text-sm text-[var(--text-muted)]">5 free scans. No credit card required.</p>
+      </div>
+    </section>
+  );
+}