Give each route its own title and canonical, and add robots.txt plus a sitemap.

The root layout was stamping the homepage title and production root onto every page. Routes now supply a page segment through one em-dash template, canonicals follow the request path, and non-production hosts disallow crawlers.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/not-found.tsx

@@ -1,11 +1,18 @@
+import type { Metadata } from "next";
 import Link from "next/link";
 import messages from "../messages/en/index";
 import { getTranslation } from "../lib/i18n/getTranslation";
+import { NO_INDEX_ROBOTS } from "../lib/siteMetadata";
 import { getGovernanceTemplateCatalogEntry } from "../lib/templates/governanceTemplateCatalog";
 import Icon from "./components/asset/icon";
 import Button from "./components/buttons/Button";
 import HeroDecor from "./components/sections/HeroBanner/HeroDecor";
 
+export const metadata: Metadata = {
+  title: messages.metadata.notFound.title,
+  robots: NO_INDEX_ROBOTS,
+};
+
 const NOT_FOUND_TEMPLATE_SLUGS = [
   "consensus",
   "do-ocracy",