chore: add sitemap.xml generation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: tianzhou

website/src/app/sitemap.ts

@@ -0,0 +1,18 @@
+import type { MetadataRoute } from 'next'
+import { getPosts } from '@/lib/blog'
+
+const BASE_URL = 'https://pgconsole.dev'
+
+export default function sitemap(): MetadataRoute.Sitemap {
+  const posts = getPosts()
+
+  return [
+    { url: BASE_URL, lastModified: new Date() },
+    { url: `${BASE_URL}/pricing`, lastModified: new Date() },
+    { url: `${BASE_URL}/blog`, lastModified: posts[0]?.date ?? new Date() },
+    ...posts.map((post) => ({
+      url: `${BASE_URL}/blog/${post.slug}`,
+      lastModified: post.date,
+    })),
+  ]
+}