fix: simplify heredoc output to fix terraform syntax error

Author: Merrino

terraform/outputs.tf

@@ -63,14 +63,5 @@ output "cloudfront_domain" {
 
 output "custom_domain_setup" {
   description = "Instructions for custom domain setup"
-  value = var.domain_name != "" && var.acm_certificate_arn == "" ? <<-EOT
-    ⚠️  Custom domain set but no ACM certificate provided!
-    
-    To enable HTTPS on ${var.domain_name}:
-    1. Create ACM certificate in us-east-1 for ${var.domain_name}
-    2. Add certificate ARN to GitHub secrets as ACM_CERTIFICATE_ARN
-    3. Re-deploy
-    
-    DNS: Point ${var.domain_name} CNAME to ${aws_cloudfront_distribution.frontend.domain_name}
-  EOT : null
+  value = var.domain_name != "" && var.acm_certificate_arn == "" ? "WARNING: Custom domain set but no ACM certificate. Add ACM_CERTIFICATE_ARN secret." : null
 }