feat: add subscription service — user auth, Stripe billing, API keys, dashboard

- NextAuth v5 with email+password credentials, JWT sessions
- Registration, login, email verification, password reset flows
- Stripe integration: Free (15/day), Starter ($5/1k/mo), Pro ($20/100k/mo)
- API key management (cb_ prefix) with hash-based validation
- Dashboard with generations history, settings, billing management
- Rate limiting: Redis daily counter (free), DB monthly (paid)
- Generate route auth: Bearer API key + session, anonymous allowed
- Worker userId propagation for generation history
- Pricing section on landing page, auth-aware navbar
- Middleware with route protection, CORS for codeboard.vectry.tech
- Docker env vars for auth, Stripe, email (smtp.migadu.com)

apps/web/src/app/(auth)/layout.tsx

@@ -0,0 +1,11 @@
+export default function AuthLayout({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  return (
+    <div className="min-h-screen bg-neutral-950 flex items-center justify-center px-4">
+      <div className="w-full max-w-md">{children}</div>
+    </div>
+  );
+}