feat: move samples into learning hub as Cookbook

- Rename samples page to /learning-hub/cookbook/
- Remove Samples from top navigation bar
- Add Cookbook to learning hub sidebar under Hands-on section
- Add Cookbook card to learning hub index page
- Add redirect from /samples/ to /learning-hub/cookbook/
- Add breadcrumb navigation back to Learning Hub

website/astro.config.mjs

@@ -7,6 +7,9 @@ export default defineConfig({
   base: "/awesome-copilot/",
   output: "static",
   integrations: [sitemap()],
+  redirects: {
+    "/samples/": "/learning-hub/cookbook/",
+  },
   build: {
     assets: "assets",
   },