Explore possibility of creating a "diff" view (Versions - v2)

# For potential future iteration

## What's involved

- [ ] Determine usefulness of "diff" view
- [ ] Play around with some "diff" code
- [ ] See if there's a way `add`/`remove` can be readable for more than a tiny change
- [ ] Examine need for reverting to a previous version #7404

## Of relevance

> In Notify, they have a similar feature where updates to notification templates have impacts on API and spreadsheets:

Start by determining whether a diff view would be useful and reviewing the related reverting discussion in issue #7404. Explore the referenced diff behavior, including whether add/remove changes remain readable beyond tiny edits. Done means documenting the usefulness, readability limitations, and whether reverting to a previous version is needed.

Written by the indexing model from the issue text.