feat: App mode - Switch to Nodes 2.0 when entering builder (#10337)

## Summary

We've had some reports of issues selecting inputs/nodes when trying to
use the builder in LiteGraph mode and due to the complexity of the
canvas system, we're going to enable Nodes 2.0 when entering the builder
to ensure the best experience.

## Changes

- **What**:  
- When entering builder select mode automatically switch to Nodes 2.0
- Extract reusable component from features toast
- Show popup telling user the mode was changed
- Add hidden setting for storing "don't show again" on the switch popup

## Review Focus
- I have not removed the LiteGraph selection code in case someone still
manages to enter the builder in LiteGraph mode, this should be cleaned
up in future

## Screenshots (if applicable)

<img width="423" height="224" alt="image"
src="https://github.com/user-attachments/assets/cc2591bc-e5dc-47ef-a3c6-91ca7b6066ff"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10337-feat-App-mode-Switch-to-Nodes-2-0-when-entering-builder-3296d73d3650818e9f3cdaac59d15609)
by [Unito](https://www.unito.io)

browser_tests/tests/appModeWidgetRename.spec.ts

@@ -30,10 +30,18 @@ async function setupSubgraphBuilder(comfyPage: 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()
-  await page.mouse.click(seedPos.x, seedPos.y)
+  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
@@ -48,9 +56,15 @@ async function setupSubgraphBuilder(comfyPage: ComfyPage) {
     )
   )
   const saveImageRef = await comfyPage.nodeOps.getNodeRefById(saveImageNodeId)
-  const saveImagePos = await saveImageRef.getPosition()
-  // Click left edge — the right side is hidden by the builder panel
-  await page.mouse.click(saveImagePos.x + 10, saveImagePos.y - 10)
+  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
@@ -80,6 +94,10 @@ test.describe('App mode widget rename', { tag: ['@ui', '@subgraph'] }, () => {
       }
     })
     await comfyPage.settings.setSetting('Comfy.UseNewMenu', 'Top')
+    await comfyPage.settings.setSetting(
+      'Comfy.AppBuilder.VueNodeSwitchDismissed',
+      true
+    )
   })
 
   test('Rename from builder input-select sidebar via menu', async ({