fix(accessibility): Correct heading hierarchy and identical links

Phase 4.4 Accessibility fixes:
- ContactFormRenderer: Change h6 info-labels to span (WhatsApp, Email, Location)
- RelatedPostRenderer: Change h5 card-title to span (semantic hierarchy)
- top-notification-bar schema: Change link_url default from # to /suscripcion-vip
  (identical links must have same destination)

Fixes: "Headings not in sequential order" and "Identical links have different purposes"

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Schemas/top-notification-bar.json

@@ -92,11 +92,11 @@
         "link_url": {
           "type": "url",
           "label": "URL del enlace",
-          "default": "#",
+          "default": "/suscripcion-vip",
           "editable": true,
           "required": true,
           "placeholder": "https://",
-          "description": "URL de destino del enlace"
+          "description": "URL de destino del enlace. Fase 4.4: Debe coincidir con otros CTAs del mismo texto"
         }
       }
     },