feat: App mode - Rework save flow (#10439)

## Summary

Users were finding the final step of the builder flow
confusing/misleading, with the "choose default mode" not actually saving
the workflow and people losing changes. This updates it to remove
"save"/"set default" as a step in the builder, and changes it to a
distinct action.

## Changes

- **What**: 
- add mode selection tab on footer toolbar
- extract reusable radio group component
- remove setting default mode dialog
- add save/save as/saved dialogs

## Screenshots (if applicable)


https://github.com/user-attachments/assets/c7439c2e-a917-4f2b-b176-f8bb8c10026d

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10439-feat-App-mode-Rework-save-flow-32d6d73d3650814781b6c7bbea685a97)
by [Unito](https://www.unito.io)

browser_tests/tests/appModeWidgetRename.spec.ts

@@ -1,89 +1,11 @@
-import type { ComfyPage } from '../fixtures/ComfyPage'
 import {
   comfyPageFixture as test,
   comfyExpect as expect
 } from '../fixtures/ComfyPage'
-import { fitToViewInstant } from '../helpers/fitToView'
-import { getPromotedWidgetNames } from '../helpers/promotedWidgets'
-
-/**
- * Convert the KSampler (id 3) in the default workflow to a subgraph,
- * enter builder, select the promoted seed widget as input and
- * SaveImage/PreviewImage as output.
- *
- * Returns the subgraph node reference for further interaction.
- */
-async function setupSubgraphBuilder(comfyPage: ComfyPage) {
-  const { page, appMode } = comfyPage
-  await comfyPage.workflow.loadWorkflow('default')
-
-  const ksampler = await comfyPage.nodeOps.getNodeRefById('3')
-  await ksampler.click('title')
-  const subgraphNode = await ksampler.convertToSubgraph()
-  await comfyPage.nextFrame()
-
-  const subgraphNodeId = String(subgraphNode.id)
-  const promotedNames = await getPromotedWidgetNames(comfyPage, subgraphNodeId)
-  expect(promotedNames).toContain('seed')
-
-  await fitToViewInstant(comfyPage)
-  await appMode.enterBuilder()
-  await appMode.goToInputs()
-
-  // Reset zoom to 1 and center on the subgraph node so click coords are accurate
-  await comfyPage.canvasOps.setScale(1)
-  await subgraphNode.centerOnNode()
-
-  // Click the promoted seed widget on the canvas to select it
-  const seedWidgetRef = await subgraphNode.getWidget(0)
-  const seedPos = await seedWidgetRef.getPosition()
-  const titleHeight = await page.evaluate(
-    () => window.LiteGraph!['NODE_TITLE_HEIGHT'] as number
-  )
-
-  await page.mouse.click(seedPos.x, seedPos.y + titleHeight)
-  await comfyPage.nextFrame()
-
-  // Select an output node
-  await appMode.goToOutputs()
-
-  const saveImageNodeId = await page.evaluate(() =>
-    String(
-      window.app!.rootGraph.nodes.find(
-        (n: { type?: string }) =>
-          n.type === 'SaveImage' || n.type === 'PreviewImage'
-      )?.id
-    )
-  )
-  const saveImageRef = await comfyPage.nodeOps.getNodeRefById(saveImageNodeId)
-  await saveImageRef.centerOnNode()
-
-  // Node is centered on screen, so click the canvas center
-  const canvasBox = await page.locator('#graph-canvas').boundingBox()
-  if (!canvasBox) throw new Error('Canvas not found')
-  await page.mouse.click(
-    canvasBox.x + canvasBox.width / 2,
-    canvasBox.y + canvasBox.height / 2
-  )
-  await comfyPage.nextFrame()
-
-  return subgraphNode
-}
-
-/** Save the workflow, reopen it, and enter app mode. */
-async function saveAndReopenInAppMode(
-  comfyPage: ComfyPage,
-  workflowName: string
-) {
-  await comfyPage.menu.topbar.saveWorkflow(workflowName)
-
-  const { workflowsTab } = comfyPage.menu
-  await workflowsTab.open()
-  await workflowsTab.getPersistedItem(workflowName).dblclick()
-  await comfyPage.nextFrame()
-
-  await comfyPage.appMode.toggleAppMode()
-}
+import {
+  saveAndReopenInAppMode,
+  setupSubgraphBuilder
+} from '../helpers/builderTestUtils'
 
 test.describe('App mode widget rename', { tag: ['@ui', '@subgraph'] }, () => {
   test.beforeEach(async ({ comfyPage }) => {