Custom/widget sections in task description

Hey, I'd like to have the possibility to have something like "widgets" in a task description for integrations. Nothing too fancy to start with, just this:

• Not editable in the frontend
• Visually distinguished from "normal" description (borders or the like)
• Can be updated by the API
• Can have the same syntax as the rest of the description (might change in the future)

So why not just update the whole description, you might ask. Well,

• The description is editable from the frontend and not distinguishable from the rest of the description
• Had to pinpoint which part of the description (start and end cursor position) should be updated and if something goes wrong, the rest of the description is broken

Bonus points for:

• making the section collabsible