Fix CSP violations and revert to stable CSS version

- Add region1.google-analytics.com to CSP headers in index.php and blog articles
- Fix manifest.json icon purpose warning by changing to "any"
- Add mobile-web-app-capable meta tag for mobile compatibility
- Revert CSS files to stable version from commit 5558f53 to resolve hero section animation issues
- Remove spam protection code that was causing layout problems

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

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

manifest.json

@@ -27,7 +27,7 @@
       "src": "assets/images/apple-touch-icon.svg",
       "sizes": "180x180",
       "type": "image/svg+xml",
-      "purpose": "apple-touch-icon"
+      "purpose": "any"
     },
     {
       "src": "assets/images/ukds-main-logo.png",