fix(web): fix doubled section prefix in doc links (404 on click)

Home page, search results, and doc page Related links all
generated hrefs as /${section}/${slug} but slug already
includes the section prefix (e.g. 'docs/websocket/contract'),
producing doubled URLs like /docs/docs/websocket/contract → 404.
Fix: href={`/${d.slug}`} everywhere.

apps/web/app/search/page.tsx

@@ -71,7 +71,7 @@ export default async function SearchPage({
             className="rounded border border-zinc-200 dark:border-zinc-800 p-3"
           >
             <Link
-              href={`/${h.doc.section}/${h.doc.slug}`}
+              href={`/${h.doc.slug}`}
               className="font-medium hover:underline"
             >
               {h.doc.title}