v1.39.0 - Alt+Drag duplicate nodes unfinished implementation

### Prerequisites

- [x] I am running the latest version of ComfyUI
- [x] I have searched existing issues to make sure this isn't a duplicate
- [x] I have tested with all custom nodes disabled ([see how](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled))

### What happened?

Alt+Drag duplicating nodes hasn't been completely implemented with standard behavior
- New duplicate node should remain attached to mouse
- New duplicate node should inherit size of source node

https://github.com/user-attachments/assets/30ab6351-c74c-4400-b075-282d82569d7a

### Steps to Reproduce

1.yes
2.
3.

### How is this affecting you?

Feature doesn't work as expected

### ComfyUI Frontend Version

1.39.0

### Browser

Chrome/Chromium

### Console Errors

```javascript

```

### Logs

```shell

```

### Additional Context

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-8386-v1-39-0-Alt-D-duplicate-nodes-unfinished-implementation-2f76d73d3650815fad77ea090e3a7a09) by [Unito](https://www.unito.io)