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/app/globals.css

@@ -0,0 +1,24 @@
+@import "tailwindcss";
+
+:root {
+  --bg: #0a0a0a;
+  --card: #141414;
+  --border: #222222;
+  --text: #e0e0e0;
+  --text-muted: #888888;
+  --grade-a: #22c55e;
+  --grade-b: #eab308;
+  --grade-c: #f97316;
+  --grade-d: #ef4444;
+  --accent: #3b82f6;
+}
+
+body {
+  background: var(--bg);
+  color: var(--text);
+  font-family: 'Inter', system-ui, sans-serif;
+}
+
+.font-mono {
+  font-family: 'JetBrains Mono', monospace;
+}