Support for Stand-In for Wan - A Lightweight and Plug-and-Play Identity Control

### Feature Idea

Was hoping for a native support of Stand-In for Wan https://github.com/WeChatCV/Stand-In

The developers already released weights for Wan 2.1 and have Wan 2.2 in plans.

### Existing Solutions

It's already implemented in kijai wan nodes, but his nodes are incompatible with native comfyui nodes and require strict use of his workflow.
https://github.com/kijai/ComfyUI-WanVideoWrapper/blob/main/example_workflows/wanvideo_Stand-In_reference_example_01.json

The devs have also released their "fix" for kijai workflow, but it still relies on kijai wrapper nodes.
https://github.com/WeChatCV/Stand-In_Preprocessor_ComfyUI

### Other

_No response_