feat(org-chart): separate fixed and auto layout previews

packages/org-chart/src/core/expanded-layout.ts

@@ -0,0 +1,10 @@
+import type { OrganizationTreeNode } from '../data/index.js';
+
+/** P5-1A preview projection only. Keep the validated hierarchy intact and
+ * expose the root's immediate groups without pretending to place descendants.
+ * P5-1B can replace this boundary with a recursive layout result shared by
+ * every runtime; neither React nor the Story owns a layout algorithm. */
+export function expandedPreviewRoots(roots: readonly OrganizationTreeNode[]): OrganizationTreeNode[] {
+  return roots.flatMap(root => root.organization.type === 'root' ? root.children : [root])
+    .map(node => ({ organization: node.organization, children: [] }));
+}