feat: add docs/experimental/sections.json endpoint to list all docs sections

apps/svelte.dev/src/routes/docs/experimental/sections.json/+server.ts

@@ -0,0 +1,18 @@
+import { docs } from '$lib/server/content';
+import { json } from '@sveltejs/kit';
+
+export const prerender = true;
+
+export function GET() {
+	return json(
+		Object.fromEntries(
+			Object.entries(docs.pages).map(([key, page]) => [
+				key,
+				{
+					metadata: { title: page.metadata.title, use_cases: page.metadata.use_cases },
+					slug: page.slug
+				}
+			])
+		)
+	);
+}