Add customTargetValue constant for custom IP/CIDR selection, implement endpointSelectValue helper to detect custom values not in target list, add isCustomEndpoint predicate to show/hide custom input fields, extend PolicyDesigner with "Custom IP/CIDR" dropdown option that reveals text input for manual IP/CIDR entry with trim on change, add placeholder examples "172.16.0.50 or 172.16.0.0/16" to guide user