Fix SEO issues found via GSC audit

- Fix broken PHP syntax in real-time data extraction article
- Fix truncated meta description on homepage
- Fix truncated titles on competitive intelligence and price monitoring pages
- Update Selenium vs Playwright article year from 2024 to 2026
- Replace no-store cache headers on homepage with private revalidation
- 301 redirect thin duplicate real-time streaming article to canonical
- Add HSTS header to data-cleaning service page
- Replace SVG og:images with PNG social card across 24 blog articles
- Add Services breadcrumb level to London, Manchester, Birmingham pages

blog/articles/python-airflow-alternatives.php

@@ -12,8 +12,8 @@ $canonical_url = "https://ukdataservices.co.uk/blog/articles/python-airflow-alte
 $keywords = "airflow alternatives python, prefect vs airflow, dagster vs airflow, flyte vs airflow, python data orchestration, data pipeline tools uk";
 $author = "Alex Kumar";
 $published_date = "2026-07-15"; // New article publication date
-$og_image = "https://ukdataservices.co.uk/assets/images/hero-data-analytics.svg";
-$twitter_card_image = "https://ukdataservices.co.uk/assets/images/hero-data-analytics.svg";
+$og_image = "https://ukdataservices.co.uk/assets/images/ukds-social-card.png";
+$twitter_card_image = "https://ukdataservices.co.uk/assets/images/ukds-social-card.png";
 
 // Breadcrumb navigation
 $breadcrumbs = [