app: shell + scificn-ui frontend (SCI-FI theme, brightened --text-muted)

scificn-ui v0.1.0 integrated copy-paste per its docs: Button/Panel/Badge/Card/Alert
in components/ui/, cn() helper in lib/utils.ts, theme tokens in app/globals.css.
Deliberate deviation from upstream: --text-muted #4A4A40 -> #6B6B5C (+12pt lightness)
for readability on the near-black background (default SCI-FI theme only). Landing page
proves the integration; no game UI yet.

app/layout.tsx

@@ -0,0 +1,15 @@
+import type { Metadata } from 'next';
+import './globals.css';
+
+export const metadata: Metadata = {
+  title: 'SpaceWanderer',
+  description: 'Turn-based space adventure — build & expand your ship, survive the void.',
+};
+
+export default function RootLayout({ children }: { children: React.ReactNode }) {
+  return (
+    <html lang="en">
+      <body>{children}</body>
+    </html>
+  );
+}