feat(docs): add documentation site and demo features

- Introduced a new documentation site for Cursor BYOK using Next.js and Fumadocs.
- Added a product demo page with a corresponding Vite configuration.
- Implemented a demo API to simulate LLM calls and responses.
- Enhanced the Makefile to include new build and development commands for the documentation.
- Updated package.json scripts for building and running the documentation site.
- Created various components and layouts for the documentation structure, including blog and user documentation sections.
- Added styling for the new components and layouts to ensure a cohesive design.
- Included a README and other necessary files for local development and deployment.

apps/docs/app/llms-full.txt/route.ts

@@ -0,0 +1,10 @@
+import { getLLMText, source } from '@/lib/source';
+
+export const revalidate = false;
+
+export async function GET() {
+  const scan = source.getPages().map(getLLMText);
+  const scanned = await Promise.all(scan);
+
+  return new Response(scanned.join('\n\n'));
+}