Hello @vincent , welcome to the community 
This looks like a perfect usecase for a component! But maybe this is actually supported through streamlit-labelstudio (a streamlit component over LabelStudio which it seems has text annotation) ?. I haven’t dug into it much, maybe @fungidick has more info on this.
In all cases I’m interested in hearing back from your progress on this 
Cheers,
Fanilo 