feat(seo): robots.txt, richer sitemap, llms.txt, manifest, OG image, JSON-LD

- Add app/robots.ts (allow crawl, disallow admin/api, sitemap URL)
- Expand sitemap to industries/[slug], accessories/[slug] and more static routes
- Add public/llms.txt (AI summary), site.webmanifest, 1200x630 og.jpg
- Layout: default OG/Twitter image, manifest, robots meta, Organization + WebSite JSON-LD
- Robot pages: canonical, OG image, Product + BreadcrumbList JSON-LD; home canonical

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/page.tsx

@@ -35,6 +35,7 @@ export const metadata: Metadata = {
     'robotics configuration UAE',
     'robot sales and demo UAE',
   ],
+  alternates: { canonical: '/' },
 };
 
 export default function HomePage() {