Feat: Alt+Drag to clone - Vue Nodes (#6789)

## Summary

Replicate the alt+drag to clone behavior present in litegraph.

## Changes

- **What**: Simplify the interaction/drag handling, now with less state!
- **What**: Alt+Click+Drag a node to clone it

## Screenshots (if applicable)



https://github.com/user-attachments/assets/469e33c2-de0c-4e64-a344-1e9d9339d528



<!-- Add screenshots or video recording to help explain your changes -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6789-WIP-Alt-Drag-to-clone-Vue-Nodes-2b16d73d36508102a871ffe97ed2831f)
by [Unito](https://www.unito.io)

---------

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

browser_tests/fixtures/ComfyPage.ts

@@ -557,7 +557,7 @@ export class ComfyPage {
   async dragAndDrop(source: Position, target: Position) {
     await this.page.mouse.move(source.x, source.y)
     await this.page.mouse.down()
-    await this.page.mouse.move(target.x, target.y)
+    await this.page.mouse.move(target.x, target.y, { steps: 100 })
     await this.page.mouse.up()
     await this.nextFrame()
   }