Add full SEO optimization for Spanglish social and language events

- Add comprehensive metadata to root layout with Open Graph, Twitter cards
- Create dynamic sitemap.ts for all pages and events
- Create robots.ts with proper allow/disallow rules
- Add JSON-LD Event structured data to event detail pages
- Add page-specific metadata to events, community, contact, FAQ pages
- Add FAQ structured data schema
- Update footer with local SEO text for Asunción, Paraguay
- Add web manifest for mobile SEO
- Create 404 page with proper noindex
- Optimize image alt text and add lazy loading
- Add NEXT_PUBLIC_SITE_URL env variable
- Add about/ folder to gitignore

frontend/src/app/robots.ts

@@ -0,0 +1,38 @@
+import { MetadataRoute } from 'next';
+
+const siteUrl = process.env.NEXT_PUBLIC_SITE_URL || 'https://spanglish.com.py';
+
+export default function robots(): MetadataRoute.Robots {
+  return {
+    rules: [
+      {
+        userAgent: '*',
+        allow: [
+          '/',
+          '/events',
+          '/events/*',
+          '/community',
+          '/contact',
+          '/faq',
+          '/legal/*',
+        ],
+        disallow: [
+          '/admin',
+          '/admin/*',
+          '/dashboard',
+          '/dashboard/*',
+          '/api',
+          '/api/*',
+          '/book',
+          '/book/*',
+          '/booking',
+          '/booking/*',
+          '/login',
+          '/register',
+          '/auth/*',
+        ],
+      },
+    ],
+    sitemap: `${siteUrl}/sitemap.xml`,
+  };
+}