openbuild.xyz

You are an AI coding agent tasked with improving openbuild.xyz's Generative Engine Optimization (GEO) readiness. This is a Next.js App Router site hosted on Vercel. Implement the following changes:

1. **Create /robots.txt**: Add a robots.txt at public/robots.txt with User-agent: * Allow: /, a Sitemap reference, and optional disallow for /api/* and /_next/* paths.

2. **Create /sitemap.xml**: Generate a dynamic sitemap using next-sitemap package or a custom app/sitemap.ts route that lists all courses (90+), challenges (123+), and bounties (58).

3. **Add JSON-LD schemas**: Inject Organization schema (name 'OpenBuild', url 'https://openbuild.xyz', logo, sameAs links to GitHub, Twitter, Bilibili) and WebSite schema (potentialAction: SearchAction) into the root layout.tsx.

4. **Add Course schemas**: For each course detail page, inject a Course JSON-LD schema with name, description, provider, educationalCredentialAwarded.

5. **Create /llms.txt**: Add a plain text file at public/llms.txt following the llms.txt standard: project name 'OpenBuild', description 'The Biggest Web3 Open-Source Community in Asia', and key internal URLs.

6. **Fix meta tags**: Update the homepage's metadata title from 'OpenBuild' to 'OpenBuild | Biggest Web3 Open-Source Community in Asia | Learn, Build & Earn'.

7. **Add canonical URLs**: Ensure every page has a <link rel="canonical"> tag pointing to its canonical URL using Next.js metadata API.

Keep changes in the Next.js App Router structure (layout.tsx, page.tsx, or app/sitemap.ts).