B2B-88: add starter kit structure and elements

packages/ui/src/makerkit/authenticity-token.tsx

@@ -0,0 +1,17 @@
+'use client';
+
+export function AuthenticityToken() {
+  const token = useCsrfToken();
+
+  return <input type="hidden" name="csrf_token" value={token} />;
+}
+
+function useCsrfToken() {
+  if (typeof window === 'undefined') return '';
+
+  return (
+    document
+      .querySelector('meta[name="csrf-token"]')
+      ?.getAttribute('content') ?? ''
+  );
+}