feat: vue nodes onboarding toggle in menu (#6671)

## Summary

Added Nodes 2.0 menu items with a toggle. 
Updated copy in banner and toast to be more descriptive.

## Screenshots (if applicable)


https://github.com/user-attachments/assets/85bf3ae4-0e0b-4e04-82c7-a26a73cbdd5b

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6671-feat-vue-nodes-onboarding-toggle-in-menu-2aa6d73d3650817d8e5bef0ad0f8bebb)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/composables/graph/useVueNodeLifecycle.ts

@@ -25,6 +25,8 @@ function useVueNodeLifecycleIndividual() {
 
   const isVueNodeToastDismissed = useVueNodesMigrationDismissed()
 
+  let hasShownMigrationToast = false
+
   const initializeNodeManager = () => {
     // Use canvas graph if available (handles subgraph contexts), fallback to app graph
     const activeGraph = comfyApp.canvas?.graph
@@ -85,7 +87,12 @@ function useVueNodeLifecycleIndividual() {
         ensureCorrectLayoutScale(
           comfyApp.canvas?.graph?.extra.workflowRendererVersion
         )
-        if (!wasEnabled && !isVueNodeToastDismissed.value) {
+        if (
+          wasEnabled === false &&
+          !isVueNodeToastDismissed.value &&
+          !hasShownMigrationToast
+        ) {
+          hasShownMigrationToast = true
           useToastStore().add({
             group: 'vue-nodes-migration',
             severity: 'info',