Migrate preview and docs packages from Eleventy to Astro (#2694)

Co-authored-by: Bartek <xbartoszdobija@gmail.com>

preview/pages/sitemap.xml.ts

@@ -0,0 +1,60 @@
+import type { APIRoute } from 'astro';
+import { site } from '@shared/lib/site';
+
+export const prerender = true;
+
+// Port of preview/pages/sitemap.liquid: one entry per page, file-style URLs
+// (build.format 'file'), index pages collapse to their directory URL.
+// Entry order mirrors the Eleventy `pages` collection: top-level pages first,
+// then nested ones, each group in reverse-alphabetical order.
+const pages = import.meta.glob('./**/*.astro');
+
+const urls = Object.keys(pages)
+	.map((file) => file.replace(/^\.\//, '').replace(/\.astro$/, '.html'))
+	.sort((a, b) => {
+		const depthA = a.split('/').length;
+		const depthB = b.split('/').length;
+		if (depthA !== depthB) return depthA - depthB;
+		// byte-wise, descending — matches the Eleventy `pages` collection order
+		return a < b ? 1 : -1;
+	})
+	.map((path) => {
+		if (path === 'index.html') return '/';
+		if (path.endsWith('/index.html')) return `/${path.slice(0, -'index.html'.length)}`;
+		return `/${path}`;
+	});
+
+const escapeXml = (value: string) =>
+	value
+		.replace(/&/g, '&amp;')
+		.replace(/</g, '&lt;')
+		.replace(/>/g, '&gt;')
+		.replace(/"/g, '&quot;')
+		.replace(/'/g, '&apos;');
+
+export const GET: APIRoute = () => {
+	const environment = process.env.NODE_ENV || 'production';
+	const baseUrl = environment !== 'development' ? site.previewUrl : '';
+	// same shape as Liquid's `'now' | date_to_xmlschema` (UTC, +00:00 suffix)
+	const lastModified = new Date().toISOString().replace(/\.\d{3}Z$/, '+00:00');
+	const entries = urls
+		.map(
+			(url) => `<url>
+	<loc>${escapeXml(`${baseUrl}${url}`)}</loc>
+	<lastmod>${lastModified}</lastmod>
+</url>`,
+		)
+		.join('\n');
+	const body = `<?xml version="1.0" encoding="UTF-8"?>
+<urlset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+
+${entries}
+</urlset>
+`;
+
+	return new Response(body, {
+		headers: {
+			'Content-Type': 'application/xml; charset=utf-8',
+		},
+	});
+};