feat(justine): isolate design system — verbatim CSS + (justine) route group

- Add app/styles/justine/01-homepage.css: rules from 01_homepage.html scoped to [data-justine]
- Replace app/(marketing) with app/(justine): layout wraps data-justine + Plus Jakarta
- JustineHomePage/Nav/Footer: original class names (btn-ink, hero-grid, …) + inline styles from HTML
- Remove app/justine-marketing.css; move /features /pricing /privacy /terms under (justine)

Made-with: Cursor

marketing/components/justine/JustineFooter.tsx

@@ -0,0 +1,32 @@
+import Link from "next/link";
+
+/** Footer from justine/01_homepage.html */
+export function JustineFooter() {
+  return (
+    <footer>
+      <div>
+        <span className="f" style={{ fontSize: 16, fontWeight: 700, color: "var(--ink)" }}>
+          vibn
+        </span>
+        <span className="footer-tagline">The fastest way from idea to product.</span>
+      </div>
+      <div className="footer-links">
+        <Link href="/#how-it-works" style={{ fontSize: 13, color: "var(--muted)", textDecoration: "none" }}>
+          How it works
+        </Link>
+        <Link href="/pricing" style={{ fontSize: 13, color: "var(--muted)", textDecoration: "none" }}>
+          Pricing
+        </Link>
+        <Link href="/privacy" style={{ fontSize: 13, color: "var(--muted)", textDecoration: "none" }}>
+          Privacy
+        </Link>
+        <Link href="/terms" style={{ fontSize: 13, color: "var(--muted)", textDecoration: "none" }}>
+          Terms
+        </Link>
+      </div>
+      <span style={{ fontSize: 12.5, color: "var(--muted)", textAlign: "right", display: "block" }}>
+        © {new Date().getFullYear()} vibn
+      </span>
+    </footer>
+  );
+}