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/Footer.tsx

@@ -0,0 +1,62 @@
+'use client';
+
+import { useState } from 'react';
+
+export default function Footer() {
+  const [email, setEmail] = useState('');
+  const [submitted, setSubmitted] = useState(false);
+
+  const handleSubmit = (e: React.FormEvent) => {
+    e.preventDefault();
+    // TODO: Store email in Supabase
+    setSubmitted(true);
+  };
+
+  return (
+    <footer className="py-16 px-4 border-t border-[var(--border)]">
+      <div className="max-w-5xl mx-auto">
+        <div className="grid md:grid-cols-2 gap-12 mb-12">
+          <div>
+            <h3 className="font-mono font-bold text-lg mb-2">
+              Beton<span className="text-[var(--accent)]">BLK</span>
+            </h3>
+            <p className="text-sm text-[var(--text-muted)] max-w-sm">
+              AI-powered parlay intelligence. Built by bettors, for bettors.
+            </p>
+          </div>
+          <div>
+            <h4 className="font-semibold mb-3">Get early access + founder pricing</h4>
+            {submitted ? (
+              <p className="text-[var(--grade-a)] text-sm">You're in. We'll be in touch.</p>
+            ) : (
+              <form onSubmit={handleSubmit} className="flex gap-2">
+                <input
+                  type="email"
+                  value={email}
+                  onChange={(e) => setEmail(e.target.value)}
+                  placeholder="your@email.com"
+                  required
+                  className="flex-1 px-4 py-2 rounded-lg bg-[var(--card)] border border-[var(--border)] text-sm text-white placeholder:text-[var(--text-muted)] focus:outline-none focus:border-[var(--accent)]"
+                />
+                <button
+                  type="submit"
+                  className="px-6 py-2 bg-[var(--accent)] text-white rounded-lg text-sm font-medium hover:opacity-90 transition"
+                >
+                  Join
+                </button>
+              </form>
+            )}
+          </div>
+        </div>
+        <div className="flex justify-between items-center text-xs text-[var(--text-muted)] border-t border-[var(--border)] pt-6">
+          <span>2026 BetonBLK. All rights reserved.</span>
+          <div className="flex gap-4">
+            <a href="#" className="hover:text-white transition">Terms</a>
+            <a href="#" className="hover:text-white transition">Privacy</a>
+            <a href="#" className="hover:text-white transition">Twitter/X</a>
+          </div>
+        </div>
+      </div>
+    </footer>
+  );
+}