refactor: encapsulate error extraction in TaskItemImpl getters (#7650)

## Summary
- Add `errorMessage` and `executionError` getters to `TaskItemImpl` that
extract error info from status messages
- Update `useJobErrorReporting` composable to use these getters instead
of standalone function
- Remove the standalone `extractExecutionError` function

This encapsulates error extraction within `TaskItemImpl`, preparing for
the Jobs API migration where the underlying data format will change but
the getter interface will remain stable.

## Test plan
- [x] All existing tests pass
- [x] New tests added for `TaskItemImpl.errorMessage` and
`TaskItemImpl.executionError` getters
- [x] TypeScript, lint, and knip checks pass

🤖 Generated with [Claude Code](https://claude.com/claude-code)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7650-refactor-encapsulate-error-extraction-in-TaskItemImpl-getters-2ce6d73d365081caae33dcc7e1e07720)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Christian Byrne <cbyrne@comfy.org>

src/composables/queue/useResultGallery.test.ts

@@ -1,35 +1,74 @@
-import { describe, it, expect } from 'vitest'
+import { createPinia, setActivePinia } from 'pinia'
+import { beforeEach, describe, expect, it } from 'vitest'
 
 import { useResultGallery } from '@/composables/queue/useResultGallery'
-import type { JobListItem } from '@/composables/queue/useJobList'
+import type { JobListItem as JobListViewItem } from '@/composables/queue/useJobList'
+import type { JobListItem } from '@/platform/remote/comfyui/jobs/jobTypes'
+import { ResultItemImpl, TaskItemImpl } from '@/stores/queueStore'
 
-type PreviewLike = { url: string; supportsPreview: boolean }
+const createResultItem = (
+  url: string,
+  supportsPreview = true
+): ResultItemImpl => {
+  const item = new ResultItemImpl({
+    filename: url,
+    subfolder: '',
+    type: 'output',
+    nodeId: 'node-1',
+    mediaType: supportsPreview ? 'images' : 'unknown'
+  })
+  // Override url getter for test matching
+  Object.defineProperty(item, 'url', { get: () => url })
+  Object.defineProperty(item, 'supportsPreview', { get: () => supportsPreview })
+  return item
+}
 
-const createPreview = (url: string, supportsPreview = true): PreviewLike => ({
-  url,
-  supportsPreview
+const createMockJob = (id: string, outputsCount = 1): JobListItem => ({
+  id,
+  status: 'completed',
+  create_time: Date.now(),
+  preview_output: null,
+  outputs_count: outputsCount,
+  priority: 0
 })
 
-const createTask = (preview?: PreviewLike) => ({
-  previewOutput: preview
-})
+const createTask = (
+  preview?: ResultItemImpl,
+  allOutputs?: ResultItemImpl[],
+  outputsCount = 1
+): TaskItemImpl => {
+  const job = createMockJob(
+    `task-${Math.random().toString(36).slice(2)}`,
+    outputsCount
+  )
+  const flatOutputs = allOutputs ?? (preview ? [preview] : [])
+  return new TaskItemImpl(job, {}, flatOutputs)
+}
 
-const createJobItem = (id: string, preview?: PreviewLike): JobListItem =>
+const createJobViewItem = (
+  id: string,
+  taskRef?: TaskItemImpl
+): JobListViewItem =>
   ({
     id,
     title: `Job ${id}`,
     meta: '',
     state: 'completed',
     showClear: false,
-    taskRef: preview ? { previewOutput: preview } : undefined
-  }) as JobListItem
+    taskRef
+  }) as JobListViewItem
 
 describe('useResultGallery', () => {
-  it('collects only previewable outputs and preserves their order', () => {
-    const previewable = [createPreview('p-1'), createPreview('p-2')]
+  beforeEach(() => {
+    setActivePinia(createPinia())
+  })
+
+  it('collects only previewable outputs and preserves their order', async () => {
+    const previewable = [createResultItem('p-1'), createResultItem('p-2')]
+    const nonPreviewable = createResultItem('skip-me', false)
     const tasks = [
       createTask(previewable[0]),
-      createTask({ url: 'skip-me', supportsPreview: false }),
+      createTask(nonPreviewable),
       createTask(previewable[1]),
       createTask()
     ]
@@ -38,28 +77,28 @@ describe('useResultGallery', () => {
       () => tasks
     )
 
-    onViewItem(createJobItem('job-1', previewable[0]))
+    await onViewItem(createJobViewItem('job-1', tasks[0]))
 
-    expect(galleryItems.value).toEqual(previewable)
+    expect(galleryItems.value).toEqual([previewable[0]])
     expect(galleryActiveIndex.value).toBe(0)
   })
 
-  it('does not change state when there are no previewable tasks', () => {
+  it('does not change state when there are no previewable tasks', async () => {
     const { galleryItems, galleryActiveIndex, onViewItem } = useResultGallery(
       () => []
     )
 
-    onViewItem(createJobItem('job-missing'))
+    await onViewItem(createJobViewItem('job-missing'))
 
     expect(galleryItems.value).toEqual([])
     expect(galleryActiveIndex.value).toBe(-1)
   })
 
-  it('activates the index that matches the viewed preview URL', () => {
+  it('activates the index that matches the viewed preview URL', async () => {
     const previewable = [
-      createPreview('p-1'),
-      createPreview('p-2'),
-      createPreview('p-3')
+      createResultItem('p-1'),
+      createResultItem('p-2'),
+      createResultItem('p-3')
     ]
     const tasks = previewable.map((preview) => createTask(preview))
 
@@ -67,37 +106,66 @@ describe('useResultGallery', () => {
       () => tasks
     )
 
-    onViewItem(createJobItem('job-2', createPreview('p-2')))
+    await onViewItem(createJobViewItem('job-2', tasks[1]))
 
-    expect(galleryItems.value).toEqual(previewable)
-    expect(galleryActiveIndex.value).toBe(1)
+    expect(galleryItems.value).toEqual([previewable[1]])
+    expect(galleryActiveIndex.value).toBe(0)
   })
 
-  it('defaults to the first entry when the clicked job lacks a preview', () => {
-    const previewable = [createPreview('p-1'), createPreview('p-2')]
+  it('defaults to the first entry when the clicked job lacks a preview', async () => {
+    const previewable = [createResultItem('p-1'), createResultItem('p-2')]
     const tasks = previewable.map((preview) => createTask(preview))
 
     const { galleryItems, galleryActiveIndex, onViewItem } = useResultGallery(
       () => tasks
     )
 
-    onViewItem(createJobItem('job-no-preview'))
+    await onViewItem(createJobViewItem('job-no-preview'))
 
     expect(galleryItems.value).toEqual(previewable)
     expect(galleryActiveIndex.value).toBe(0)
   })
 
-  it('defaults to the first entry when no gallery item matches the preview URL', () => {
-    const previewable = [createPreview('p-1'), createPreview('p-2')]
+  it('defaults to the first entry when no gallery item matches the preview URL', async () => {
+    const previewable = [createResultItem('p-1'), createResultItem('p-2')]
     const tasks = previewable.map((preview) => createTask(preview))
 
     const { galleryItems, galleryActiveIndex, onViewItem } = useResultGallery(
       () => tasks
     )
 
-    onViewItem(createJobItem('job-mismatch', createPreview('missing')))
+    const taskWithMismatchedPreview = createTask(createResultItem('missing'))
+    await onViewItem(
+      createJobViewItem('job-mismatch', taskWithMismatchedPreview)
+    )
 
-    expect(galleryItems.value).toEqual(previewable)
+    expect(galleryItems.value).toEqual([createResultItem('missing')])
+    expect(galleryActiveIndex.value).toBe(0)
+  })
+
+  it('loads full outputs when task has only preview outputs', async () => {
+    const previewOutput = createResultItem('preview-1')
+    const fullOutputs = [
+      createResultItem('full-1'),
+      createResultItem('full-2'),
+      createResultItem('full-3')
+    ]
+
+    // Create a task with outputsCount > 1 to trigger lazy loading
+    const job = createMockJob('task-1', 3)
+    const task = new TaskItemImpl(job, {}, [previewOutput])
+
+    // Mock loadFullOutputs to return full outputs
+    const loadedTask = new TaskItemImpl(job, {}, fullOutputs)
+    task.loadFullOutputs = async () => loadedTask
+
+    const { galleryItems, galleryActiveIndex, onViewItem } = useResultGallery(
+      () => [task]
+    )
+
+    await onViewItem(createJobViewItem('job-1', task))
+
+    expect(galleryItems.value).toEqual(fullOutputs)
     expect(galleryActiveIndex.value).toBe(0)
   })
 })