feat(docs): enhance documentation site with internationalization and layout updates

- Updated the demo API to support locale-based content rendering.
- Refactored the main layout to accommodate language-specific metadata and routing.
- Introduced new components for blog and documentation pages, ensuring proper language handling.
- Added styles for improved UI consistency across different sections.
- Removed deprecated layout files and streamlined the structure for better maintainability.

apps/docs/app/[lang]/llms.mdx/docs/[[...slug]]/route.ts

@@ -0,0 +1,29 @@
+import { getLLMText, getPageMarkdownUrl, source } from '@/lib/source';
+import { i18n } from '@/lib/i18n';
+import { notFound } from 'next/navigation';
+
+export const revalidate = false;
+
+export async function GET(
+  _req: Request,
+  { params }: RouteContext<'/[lang]/llms.mdx/docs/[[...slug]]'>,
+) {
+  const { lang, slug } = await params;
+  const page = source.getPage(slug?.slice(0, -1), lang);
+  if (!page) notFound();
+
+  return new Response(await getLLMText(page), {
+    headers: {
+      'Content-Type': 'text/markdown',
+    },
+  });
+}
+
+export function generateStaticParams() {
+  return i18n.languages.flatMap((lang) =>
+    source.getPages(lang).map((page) => ({
+      lang,
+      slug: getPageMarkdownUrl(page).segments,
+    })),
+  );
+}