Lightsail instance has no publicly accessible ports

# Terraform: ensure no public ports are open on the Lightsail instance
resource "aws_lightsail_instance_public_ports" "<example_resource_name>" {
  instance_name = "<example_resource_name>"

  # Critical: no port_info blocks -> no public ports are configured (closes all)
  dynamic "port_info" {
    for_each = []
    content {
      from_port = 0
      to_port   = 0
      protocol  = "tcp"
    }
  }
}

# CloudFormation: remove all public ports from a Lightsail instance
Resources:
  ClosePublicPorts:
    Type: AWS::Lightsail::InstancePublicPorts
    Properties:
      InstanceName: <example_resource_name>
      PortInfos: []  # Critical: empty list clears all public ports so the instance is not publicly exposed