chore: vendor client into main repo

client/components/useClientOnlyValue.web.ts

@@ -0,0 +1,12 @@
+import React from 'react';
+
+// `useEffect` is not invoked during server rendering, meaning
+// we can use this to determine if we're on the server or not.
+export function useClientOnlyValue<S, C>(server: S, client: C): S | C {
+  const [value, setValue] = React.useState<S | C>(server);
+  React.useEffect(() => {
+    setValue(client);
+  }, [client]);
+
+  return value;
+}