feat: add logout page

frontend/pages/logout.tsx

@@ -0,0 +1,19 @@
+import { useRouter } from "next/router";
+import { useEffect } from "react";
+import { useRecoilState } from "recoil";
+import Loading from "../components/Loading";
+import { userState } from "../lib/state";
+
+export default function Logout() {
+  const router = useRouter();
+  const [_, setUser] = useRecoilState(userState);
+
+  useEffect(() => {
+    localStorage.removeItem("pronouns-token");
+    setUser(null);
+
+    router.push("/");
+  }, []);
+
+  return <Loading />;
+}