[Feature Request]: API for integrating with the Mask Editor

### Is there an existing issue for this?

- [x] I have searched the existing issues and checked the recent builds/commits

### What would your feature do ?

Enable custom node developers to integrate with/add features to the mask editor

### Proposed workflow

Custom node developer uses the API to, for instance
- add custom tools
- integrate with external models (such as a segment model)
- read and write images and masks dynamically

### Additional information

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-3720-Feature-Request-API-for-integrating-with-the-Mask-Editor-1e66d73d3650811f9d7ae394897bb6dc) by [Unito](https://www.unito.io)