TenderRadar website with CSS fixes

- Fixed footer logo contrast (dark → white on dark background)
- Fixed avatar sizing and gradient contrasts
- Fixed testimonial layout with flexbox
- Fixed signup form contrast and LastPass icon overlap
- Added responsive company logos section
- Fixed FAQ accordion CSS
- All CSS improvements for WCAG compliance

robots.txt

@@ -0,0 +1,16 @@
+# TenderRadar - Robots.txt
+# https://tenderradar.co.uk/robots.txt
+
+User-agent: *
+Allow: /
+Disallow: /dashboard.html
+Disallow: /dashboard
+Disallow: /profile.html
+Disallow: /profile
+Disallow: /alerts.html
+Disallow: /alerts
+Disallow: /api/
+Disallow: /admin/
+
+# Sitemap location
+Sitemap: https://tenderradar.co.uk/sitemap.xml