in script.js [923:936]
function addNewManagementGroup() {
const newMg = {
archetypes: ["empty"],
display_name: "New Management Group",
exists: false,
id: "new-mg-" + Date.now(),
parent_id: null
};
currentData.management_groups.push(newMg);
renderManagementGroups();
selectManagementGroup(newMg.id);
updateJsonPreview();
}