Add leaflet-powered brewery map

web/frontend/app/components/ClientOnly.tsx

@@ -0,0 +1,21 @@
+import { useSyncExternalStore, type ReactNode } from 'react';
+
+interface ClientOnlyProps {
+    children: () => ReactNode;
+    fallback?: ReactNode;
+}
+
+const noop = () => undefined;
+const emptySubscribe = () => noop;
+
+const ClientOnly = ({ children, fallback = null }: ClientOnlyProps) => {
+    const mounted = useSyncExternalStore(
+        emptySubscribe,
+        () => true,
+        () => false,
+    );
+
+    return mounted ? children() : fallback;
+};
+
+export default ClientOnly;