feat(queue): introduce queue notification banners and remove completion summary flow (#8740)

## Summary
Replace the old completion-summary overlay path with queue notification
banners for queueing/completed/failed lifecycle feedback.

## Key changes
- Added `QueueNotificationBanner`, `QueueNotificationBannerHost`,
stories, and tests.
- Added `useQueueNotificationBanners` to handle:
  - immediate `queuedPending` on `promptQueueing`
  - transition to `queued` on `promptQueued` (request-id aware)
  - completed/failed notification sequencing from finished batch history
  - timed notification queueing/dismissal
- Removed completion-summary implementation:
  - `useCompletionSummary`
  - `CompletionSummaryBanner`
  - `QueueOverlayEmpty`
- Simplified `QueueProgressOverlay` to `hidden | active | expanded`
states.
- Top menu behavior:
  - restored `QueueInlineProgressSummary` as separate UI
  - ordering is inline summary first, notification banner below
- notification banner remains under the top menu section (not teleported
to floating actionbar target)
- Kept established API-event signaling pattern
(`promptQueueing`/`promptQueued`) instead of introducing a separate bus.
- Updated tests for top-menu visibility/ordering and notification
behavior across QPOV2 enabled/disabled.

## Notes
- Completion notifications now support stacked thumbnails (cap: 3).
-
https://www.figma.com/design/LVilZgHGk5RwWOkVN6yCEK/Queue-Progress-Modal?node-id=3843-20314&m=dev

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8740-feat-Queue-Notification-Toasts-3016d73d3650814c8a50d9567a40f44d)
by [Unito](https://www.unito.io)

src/components/TopMenuSection.vue

@@ -105,7 +105,7 @@
       </div>
     </div>
 
-    <div>
+    <div class="flex flex-col items-end gap-1">
       <Teleport
         v-if="inlineProgressSummaryTarget"
         :to="inlineProgressSummaryTarget"
@@ -121,6 +121,10 @@
         class="pr-1"
         :hidden="isQueueOverlayExpanded"
       />
+      <QueueNotificationBannerHost
+        v-if="shouldShowQueueNotificationBanners"
+        class="pr-1"
+      />
     </div>
   </div>
 </template>
@@ -136,6 +140,7 @@ import { useI18n } from 'vue-i18n'
 import ComfyActionbar from '@/components/actionbar/ComfyActionbar.vue'
 import SubgraphBreadcrumb from '@/components/breadcrumb/SubgraphBreadcrumb.vue'
 import QueueInlineProgressSummary from '@/components/queue/QueueInlineProgressSummary.vue'
+import QueueNotificationBannerHost from '@/components/queue/QueueNotificationBannerHost.vue'
 import QueueProgressOverlay from '@/components/queue/QueueProgressOverlay.vue'
 import ActionBarButtons from '@/components/topbar/ActionBarButtons.vue'
 import CurrentUserButton from '@/components/topbar/CurrentUserButton.vue'
@@ -204,6 +209,9 @@ const isQueueProgressOverlayEnabled = computed(
 const shouldShowInlineProgressSummary = computed(
   () => isQueuePanelV2Enabled.value && isActionbarEnabled.value
 )
+const shouldShowQueueNotificationBanners = computed(
+  () => isActionbarEnabled.value
+)
 const progressTarget = ref<HTMLElement | null>(null)
 function updateProgressTarget(target: HTMLElement | null) {
   progressTarget.value = target