[Feature request]: Mark widget inputs as intended for user input and include flags in JSON export

### Feature Idea

When writing a frontend for a ComfyUI workflow, typically I want to fix most of the inputs and hide them from nontechnical users, and only expose a few.

For any given input on any given node, I'd like to be able to select that node in the context menu and mark it as an intended input. This should be visually indicated in the editor GUI. This would then be reflected in the JSON export, which could be quickly parsed by a frontend application.

This feature would reduce the need to write custom logic per workflow.

### Existing Solutions

_No response_

### Other

_No response_