Update files

packages/app/src/lib/overlay-root.ts

@@ -0,0 +1,25 @@
+/**
+ * Shared overlay root for web portals (modals, toasts, etc.)
+ * This ensures consistent stacking order by controlling a single overlay container.
+ *
+ * Z-index scale within overlay root:
+ * - Modal backdrop/content: 10
+ * - Toast: 20
+ */
+export function getOverlayRoot(): HTMLElement {
+  let el = document.getElementById("overlay-root");
+  if (!el) {
+    el = document.createElement("div");
+    el.id = "overlay-root";
+    el.style.position = "fixed";
+    el.style.inset = "0";
+    el.style.pointerEvents = "none";
+    document.body.appendChild(el);
+  }
+  return el;
+}
+
+export const OVERLAY_Z = {
+  modal: 10,
+  toast: 20,
+} as const;