feat: add site footer

components/layout/Footer.tsx

@@ -0,0 +1,9 @@
+export function Footer() {
+  return (
+    <footer className="border-t border-border mt-20 py-8 text-center">
+      <p className="font-mono text-sm text-ink-soft">
+        © {new Date().getFullYear()} blog. All rights reserved.
+      </p>
+    </footer>
+  )
+}