[feat] Update history API to v2 array format and add comprehensive tests

- Migrate from object-based to array-based history response format
- Update /history endpoint to /history_v2 with max_items parameter
- Add lazy loading of workflows via /history_v2/:prompt_id endpoint
- Implement comprehensive browser tests for history API functionality
- Add unit tests for API methods and queue store
- Update TaskItemImpl to support history workflow loading
- Add proper error handling and edge case coverage
- Follow established test patterns for better maintainability

This change improves performance by reducing initial payload size
and enables on-demand workflow loading for history items.

src/services/workflowService.ts

@@ -5,10 +5,12 @@ import { LGraph, LGraphCanvas } from '@/lib/litegraph/src/litegraph'
 import type { SerialisableGraph, Vector2 } from '@/lib/litegraph/src/litegraph'
 import { useWorkflowThumbnail } from '@/renderer/thumbnail/composables/useWorkflowThumbnail'
 import { ComfyWorkflowJSON } from '@/schemas/comfyWorkflowSchema'
+import { api } from '@/scripts/api'
 import { app } from '@/scripts/app'
 import { blankGraph, defaultGraph } from '@/scripts/defaultGraph'
 import { downloadBlob } from '@/scripts/utils'
 import { useDomWidgetStore } from '@/stores/domWidgetStore'
+import { TaskItemImpl } from '@/stores/queueStore'
 import { useSettingStore } from '@/stores/settingStore'
 import { useToastStore } from '@/stores/toastStore'
 import { ComfyWorkflow, useWorkflowStore } from '@/stores/workflowStore'
@@ -154,6 +156,32 @@ export const useWorkflowService = () => {
     await app.loadGraphData(blankGraph)
   }
 
+  /**
+   * Load a workflow from a task item (queue/history)
+   * For history items, fetches workflow data from /history_v2/{prompt_id}
+   * @param task The task item to load the workflow from
+   */
+  const loadTaskWorkflow = async (task: TaskItemImpl) => {
+    let workflowData = task.workflow
+
+    // History items don't include workflow data - fetch from API
+    if (task.isHistory) {
+      const promptId = task.prompt.prompt_id
+      if (promptId) {
+        workflowData = (await api.getWorkflowFromHistory(promptId)) || undefined
+      }
+    }
+
+    if (!workflowData) {
+      return
+    }
+
+    await app.loadGraphData(toRaw(workflowData))
+    if (task.outputs) {
+      app.nodeOutputs = toRaw(task.outputs)
+    }
+  }
+
   /**
    * Reload the current workflow
    * This is used to refresh the node definitions update, e.g. when the locale changes.
@@ -402,6 +430,7 @@ export const useWorkflowService = () => {
     saveWorkflow,
     loadDefaultWorkflow,
     loadBlankWorkflow,
+    loadTaskWorkflow,
     reloadCurrentWorkflow,
     openWorkflow,
     closeWorkflow,