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/composables/queue/useJobList.test.ts

@@ -5,7 +5,6 @@ import type { Ref } from 'vue'
 
 import { useJobList } from '@/composables/queue/useJobList'
 import type { JobState } from '@/types/queue'
-import { buildJobDisplay } from '@/utils/queueDisplay'
 import type { BuildJobDisplayCtx } from '@/utils/queueDisplay'
 import type { TaskItemImpl } from '@/stores/queueStore'
 
@@ -256,78 +255,6 @@ describe('useJobList', () => {
     return api!
   }
 
-  it('tracks recently added pending jobs and clears the hint after expiry', async () => {
-    vi.useFakeTimers()
-    queueStoreMock.pendingTasks = [
-      createTask({ promptId: '1', queueIndex: 1, mockState: 'pending' })
-    ]
-
-    const { jobItems } = initComposable()
-    await flush()
-
-    jobItems.value
-    expect(buildJobDisplay).toHaveBeenCalledWith(
-      expect.anything(),
-      'pending',
-      expect.objectContaining({ showAddedHint: true })
-    )
-
-    vi.mocked(buildJobDisplay).mockClear()
-    await vi.advanceTimersByTimeAsync(3000)
-    await flush()
-
-    jobItems.value
-    expect(buildJobDisplay).toHaveBeenCalledWith(
-      expect.anything(),
-      'pending',
-      expect.objectContaining({ showAddedHint: false })
-    )
-  })
-
-  it('removes pending hint immediately when the task leaves the queue', async () => {
-    vi.useFakeTimers()
-    const taskId = '2'
-    queueStoreMock.pendingTasks = [
-      createTask({ promptId: taskId, queueIndex: 1, mockState: 'pending' })
-    ]
-
-    const { jobItems } = initComposable()
-    await flush()
-    jobItems.value
-
-    queueStoreMock.pendingTasks = []
-    await flush()
-    expect(vi.getTimerCount()).toBe(0)
-
-    vi.mocked(buildJobDisplay).mockClear()
-    queueStoreMock.pendingTasks = [
-      createTask({ promptId: taskId, queueIndex: 2, mockState: 'pending' })
-    ]
-    await flush()
-    jobItems.value
-    expect(buildJobDisplay).toHaveBeenCalledWith(
-      expect.anything(),
-      'pending',
-      expect.objectContaining({ showAddedHint: true })
-    )
-  })
-
-  it('cleans up timeouts on unmount', async () => {
-    vi.useFakeTimers()
-    queueStoreMock.pendingTasks = [
-      createTask({ promptId: '3', queueIndex: 1, mockState: 'pending' })
-    ]
-
-    initComposable()
-    await flush()
-    expect(vi.getTimerCount()).toBeGreaterThan(0)
-
-    wrapper?.unmount()
-    wrapper = null
-    await flush()
-    expect(vi.getTimerCount()).toBe(0)
-  })
-
   it('sorts all tasks by create time', async () => {
     queueStoreMock.pendingTasks = [
       createTask({