Integrate the new UI pages with the working backend for the rate_summary task. This also migrates some pages to properly link up authorization flows. Some cruft is still in

website/src/middleware.ts

@@ -0,0 +1,8 @@
+export { default } from "next-auth/middleware";
+
+/**
+ * Guards all pages under `/grading` and redirects them to the sign in page.
+ */
+export const config = {
+  matcher: ["/grading/:path*"],
+};