feat: remove contact form and switch canonical domain to mnqcatering.com

Drop the non-functional contact form (no backend wired up) and keep
the WhatsApp/phone contact path as the single call to action. Also
point site config, robots.txt, llms.txt, and every on-page domain
reference at www.mnqcatering.com ahead of the DNS cutover.

public/llms.txt

@@ -1,6 +1,6 @@
 MNQ Catering y Evento
 
-- Canonical domain: https://mnq.elkazurrotaberna.es
+- Canonical domain: https://www.mnqcatering.com
 - Business type: Premium catering service
 - Services: Bodas, eventos corporativos, reuniones familiares
 - Primary contact channels: WhatsApp (+34 678 17 15 13), phone (+34 678 17 15 13)

public/robots.txt

@@ -1,4 +1,4 @@
 User-agent: *
 Allow: /
 
-Sitemap: https://mnq.elkazurrotaberna.es/sitemap-index.xml
+Sitemap: https://www.mnqcatering.com/sitemap-index.xml