Dragging sidebar splitter over Vue 2.0 node headers causes unintended node movement

### 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?

When dragging the sidebar splitter (resize handle) and the cursor passes over a Vue 2.0 node header, the node unexpectedly starts moving. This occurs with both the left sidebar and right sidebar splitters.

The splitter drag operation should not interact with or trigger node movement - these should be independent interactions.

### Steps to Reproduce

1. Open a workflow with Vue 2.0 nodes (nodes using the new Vue-based rendering)
2. Start dragging either the left or right sidebar splitter to resize the panel
3. While dragging, move the cursor over a Vue 2.0 node header area
4. Observe that the node starts moving along with the splitter drag

https://github.com/user-attachments/assets/c217484f-9fa2-45cf-a4b2-8fd1286ae317

### How is this affecting you?

Feature doesn't work as expected

### ComfyUI Frontend Version

Latest

### Browser

Chrome/Chromium

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-7150-Dragging-sidebar-splitter-over-Vue-2-0-node-headers-causes-unintended-node-movement-2bf6d73d36508196a70bff60713f0042) by [Unito](https://www.unito.io)