docs(analytics): add analytics to docs

docs/astro.config.mjs

@@ -1,8 +1,15 @@
 import starlight from '@astrojs/starlight';
+import vercel from '@astrojs/vercel/serverless';
 import { defineConfig } from 'astro/config';
 
 // https://astro.build/config
 export default defineConfig({
+  output: 'server',
+  adapter: vercel({
+    webAnalytics: {
+      enabled: true,
+    },
+  }),
   integrations: [
     starlight({
       title: 'Angular Challenges',