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/components/layout/Footer.tsx

@@ -29,6 +29,10 @@ export default function Footer() {
             <p className="mt-3 text-gray-600 max-w-md">
               {t('footer.tagline')}
             </p>
+            {/* Local SEO text */}
+            <p className="mt-2 text-sm text-gray-500">
+              Language Exchange Events in Asunción, Paraguay
+            </p>
           </div>
 
           {/* Quick Links */}