fix(web): portal timeline overlays above stacked panels

apps/web/src/components/timeline/BatchAssignPopover.tsx

@@ -2,6 +2,7 @@
 
 import { clsx } from "clsx";
 import { useEffect, useRef, useState } from "react";
+import { createPortal } from "react-dom";
 import { AllocationStatus } from "@capakraken/shared";
 import { trpc } from "~/lib/trpc/client.js";
 import { useInvalidateTimeline } from "~/hooks/useInvalidatePlanningViews.js";
@@ -96,7 +97,7 @@ export function BatchAssignPopover({
   const canAssign =
     !!selectedProjectId && resourceIds.length > 0 && hoursPerDay > 0;
 
-  return (
+  const popover = (
     <div
       ref={ref}
       className="fixed top-1/2 left-1/2 -translate-x-1/2 -translate-y-1/2 z-[60] w-[360px] bg-white dark:bg-gray-800 border border-gray-200 dark:border-gray-700 rounded-xl shadow-2xl dark:shadow-black/40 overflow-hidden"
@@ -254,4 +255,6 @@ export function BatchAssignPopover({
       </div>
     </div>
   );
+
+  return typeof document === "undefined" ? popover : createPortal(popover, document.body);
 }