feat: Add cancel button to active job card in grid view (#8264)

## Summary
Add a cancel (x) button overlay to active job cards in grid view,
matching the existing list view behavior.

## Changes
- **What**: Added hover-triggered cancel button to `ActiveJobCard.vue`
using the existing `useJobActions` composable
- Button appears on hover for jobs in cancellable states (pending,
initialization, running)

<img width="1710" height="1107" alt="스크린샷 2026-01-23 오후 5 11 04"
src="https://github.com/user-attachments/assets/31a6b6d1-46e7-49c4-a253-92260cb28514"
/>
<img width="1710" height="1107" alt="스크린샷 2026-01-23 오후 5 10 59"
src="https://github.com/user-attachments/assets/b559a81e-8e62-4858-b8e7-92de9caa2919"
/>


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8264-feat-Add-cancel-button-to-active-job-card-in-grid-view-2f16d73d3650817d83f0dd3b955759cb)
by [Unito](https://www.unito.io)

---------

Co-authored-by: GitHub Action <action@github.com>

src/platform/assets/components/ActiveMediaAssetCard.test.ts

@@ -1,4 +1,5 @@
 import { mount } from '@vue/test-utils'
+import { computed } from 'vue'
 import { describe, expect, it, vi } from 'vitest'
 import { createI18n } from 'vue-i18n'
 
@@ -6,6 +7,18 @@ import ActiveJobCard from './ActiveMediaAssetCard.vue'
 
 import type { JobListItem } from '@/composables/queue/useJobList'
 
+vi.mock('@/composables/queue/useJobActions', () => ({
+  useJobActions: () => ({
+    cancelAction: {
+      icon: 'icon-[lucide--x]',
+      label: 'Cancel',
+      variant: 'destructive'
+    },
+    canCancelJob: computed(() => false),
+    runCancelJob: vi.fn()
+  })
+}))
+
 vi.mock('@/composables/useProgressBarBackground', () => ({
   useProgressBarBackground: () => ({
     progressBarPrimaryClass: 'bg-blue-500',