- Updated backend/src/app.js to allow Cloudflare domains in CSP - Added https://challenges.cloudflare.com to scriptSrc - Added https://challenges.cloudflare.com to connectSrc - Added https://challenges.cloudflare.com to frameSrc - Removed duplicate CSP from nginx/conf.d.prod/default.conf - CSP is now managed only by backend Helmet middleware - Prevents conflicting security policies