SEO: rewrite meta descriptions, add FAQ schema, add CTA box to all articles

- Rewrite meta descriptions on 4 high-impression articles (churn, compliance, data quality, ecommerce)
- Fix data-quality-validation-pipelines title & description to capture zero-click statistical validation queries
- Add FAQPage schema to churn prediction and data quality articles
- Add service CTA box to article-footer.php (appears on all blog articles)
- Add responsive CSS for CTA box in main.css

includes/article-footer.php

@@ -97,6 +97,21 @@ $filtered_articles = array_filter($category_articles, function($article) use ($c
 $display_articles = array_slice($filtered_articles, 0, 3);
 ?>
 
+
+<!-- Service CTA Box — inserted by SEO update Feb 2026 -->
+<section class="article-cta">
+    <div class="cta-inner">
+        <div class="cta-text">
+            <h3>Need data for your business?</h3>
+            <p>UK Data Services delivers GDPR-compliant web scraping, data extraction, and analytics — tailored to your industry. 99.8% accuracy, fast turnaround, no long-term contracts.</p>
+        </div>
+        <div class="cta-actions">
+            <a href="/quote.php" class="btn btn-primary">Get a Free Quote</a>
+            <a href="/services/web-scraping.php" class="btn btn-secondary">See Our Services</a>
+        </div>
+    </div>
+</section>
+
 <section class="related-articles">
     <h2>Related Articles</h2>
     <div class="related-grid">