feat(historyV2): create sythetic queue priority (#6336)

## Summary

Create display priority based on execution success timestamps.

Next up is displaying in progress prompts in the queue.

## Review Focus

@DrJKL and I discussed logic and decided for history, execution success
(when the prompt finishes) is the best way to assign priority.

This does differ from existing cloud logic which uses execution start
time.

For prompt progress I intend to create a priority for them based on
start time.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6336-feat-historyV2-create-sythetic-queue-priority-2996d73d365081ffa3a0f8071c178066)
by [Unito](https://www.unito.io)

tests-ui/tests/platform/remote/comfyui/history/adapters/v2ToV1Adapter.test.ts

@@ -11,6 +11,10 @@ import {
   expectedV1Fixture,
   historyV2Fixture
 } from '@tests-ui/fixtures/historyFixtures'
+import {
+  historyV2FiveItemsSorting,
+  historyV2WithMissingTimestamp
+} from '@tests-ui/fixtures/historySortingFixtures'
 
 describe('mapHistoryV2toHistory', () => {
   describe('fixture validation', () => {
@@ -38,7 +42,7 @@ describe('mapHistoryV2toHistory', () => {
     it('should transform prompt to V1 tuple [priority, id, {}, extra_data, outputNodeIds]', () => {
       const firstItem = history[0]
 
-      expect(firstItem.prompt[0]).toBe(24)
+      expect(firstItem.prompt[0]).toBe(1) // Synthetic priority based on timestamp
       expect(firstItem.prompt[1]).toBe('complete-item-id')
       expect(firstItem.prompt[2]).toEqual({}) // history v2 does not return this data
       expect(firstItem.prompt[3]).toMatchObject({ client_id: 'test-client' })
@@ -117,4 +121,70 @@ describe('mapHistoryV2toHistory', () => {
       expect(history[0].prompt[3].client_id).toBeUndefined()
     })
   })
+
+  describe('timestamp-based priority assignment', () => {
+    it('assigns priority 0 to items without execution_success timestamp', () => {
+      const result = mapHistoryV2toHistory(historyV2WithMissingTimestamp)
+
+      expect(result).toHaveLength(3)
+
+      const item1000 = result.find(
+        (item) => item.prompt[1] === 'item-timestamp-1000'
+      )
+      const item2000 = result.find(
+        (item) => item.prompt[1] === 'item-timestamp-2000'
+      )
+      const itemNoTimestamp = result.find(
+        (item) => item.prompt[1] === 'item-no-timestamp'
+      )
+
+      expect(item1000).toBeDefined()
+      expect(item2000).toBeDefined()
+      expect(itemNoTimestamp).toBeDefined()
+      if (!item1000 || !item2000 || !itemNoTimestamp) {
+        throw new Error('Expected items not found in result')
+      }
+
+      expect(item2000.prompt[0]).toBe(2)
+      expect(item1000.prompt[0]).toBe(1)
+      expect(itemNoTimestamp.prompt[0]).toBe(0)
+    })
+
+    it('correctly sorts and assigns priorities for multiple items', () => {
+      const result = mapHistoryV2toHistory(historyV2FiveItemsSorting)
+
+      expect(result).toHaveLength(5)
+
+      const item1000 = result.find(
+        (item) => item.prompt[1] === 'item-timestamp-1000'
+      )
+      const item2000 = result.find(
+        (item) => item.prompt[1] === 'item-timestamp-2000'
+      )
+      const item3000 = result.find(
+        (item) => item.prompt[1] === 'item-timestamp-3000'
+      )
+      const item4000 = result.find(
+        (item) => item.prompt[1] === 'item-timestamp-4000'
+      )
+      const item5000 = result.find(
+        (item) => item.prompt[1] === 'item-timestamp-5000'
+      )
+
+      expect(item1000).toBeDefined()
+      expect(item2000).toBeDefined()
+      expect(item3000).toBeDefined()
+      expect(item4000).toBeDefined()
+      expect(item5000).toBeDefined()
+      if (!item1000 || !item2000 || !item3000 || !item4000 || !item5000) {
+        throw new Error('Expected items not found in result')
+      }
+
+      expect(item5000.prompt[0]).toBe(5)
+      expect(item4000.prompt[0]).toBe(4)
+      expect(item3000.prompt[0]).toBe(3)
+      expect(item2000.prompt[0]).toBe(2)
+      expect(item1000.prompt[0]).toBe(1)
+    })
+  })
 })