Refine use cases rule examples

app/(marketing-case-study)/layout.tsx

@@ -0,0 +1,14 @@
+import type { ReactNode } from "react";
+
+/** Full-viewport case-study surfaces (completed rule demos) — no marketing footer. */
+export default function MarketingCaseStudyLayout({
+  children,
+}: {
+  children: ReactNode;
+}) {
+  return (
+    <main className="flex h-dvh min-h-0 flex-col overflow-hidden">
+      {children}
+    </main>
+  );
+}