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>

Public/RelatedPost/Infrastructure/Ui/RelatedPostRenderer.php

@@ -312,7 +312,7 @@ final class RelatedPostRenderer implements RendererInterface
         $html .= '<div class="card h-100">';
         $html .= '<div class="card-body d-flex align-items-center justify-content-center">';
         $html .= sprintf(
-            '<h5 class="card-title h6 mb-0 text-center">%s</h5>',
+            '<span class="card-title d-block h6 mb-0 text-center">%s</span>',
             esc_html($title)
         );
         $html .= '</div>';