fix(emcn): stop calendar content bleeding through the modal backdrop (#5311)

* fix(emcn): promote modal overlay + content wrapper to own compositing layers

The backdrop-blur overlay did not reliably paint above page content the
browser had GPU-promoted (position: sticky headers and z-indexed absolutes
inside a scroll container, e.g. the scheduled-tasks calendar), so those
composited layers bled through the overlay despite its higher z-index.
Force the overlay and the content wrapper onto their own compositing
layers via translateZ(0) so the compositor honors stacking order.

Inherent since the calendar shipped (#4979), not a refactor regression.

* Revert "fix(emcn): promote modal overlay + content wrapper to own compositing layers"

This reverts commit 52145edc97.

* fix(ui): import calendar icon not calendar widget from emcn

* fix(ui): fix calendar icon emcn mismatch

---------

Co-authored-by: Theodore Li <theo@sim.ai>

apps/sim/app/workspace/[workspaceId]/scheduled-tasks/components/task-delete-dialog/task-delete-dialog.tsx

@@ -1,13 +1,13 @@
 'use client'
 
 import {
-  Calendar,
   ChipConfirmModal,
   ChipModal,
   ChipModalBody,
   ChipModalFooter,
   ChipModalHeader,
 } from '@sim/emcn'
+import { Calendar } from '@sim/emcn/icons'
 import type { ScheduledTask } from '@/app/workspace/[workspaceId]/scheduled-tasks/utils/schedule-events'
 
 interface TaskDeleteDialogProps {

apps/sim/app/workspace/[workspaceId]/scheduled-tasks/components/task-details-modal/task-details-modal.tsx

@@ -1,6 +1,5 @@
 'use client'
 import {
-  Calendar,
   ChipModal,
   ChipModalBody,
   ChipModalField,
@@ -9,6 +8,7 @@ import {
   chipFieldSurfaceClass,
   cn,
 } from '@sim/emcn'
+import { Calendar } from '@sim/emcn/icons'
 import { format } from 'date-fns'
 import { useParams } from 'next/navigation'
 import {

apps/sim/app/workspace/[workspaceId]/scheduled-tasks/components/task-modal/task-modal.tsx

@@ -2,7 +2,6 @@
 
 import { useEffect, useRef, useState } from 'react'
 import {
-  Calendar,
   ChipDatePicker,
   ChipModal,
   ChipModalFooter,
@@ -11,6 +10,7 @@ import {
   ChipModalPromptBody,
   ChipTimePicker,
 } from '@sim/emcn'
+import { Calendar } from '@sim/emcn/icons'
 import { format } from 'date-fns'
 import { useParams } from 'next/navigation'
 import { wallClockNow, zonedWallClockToUtc } from '@/lib/core/utils/timezone'