Show me the diff between the app updates

When I am deciding whether I want a particular app to update in the next bench deploy, it will be useful if I can see the diff of the file changes. Even better UX would be better to tell me whether it is going to result in a migrate or a pull-only update. Basically, show me as much useful information as possible so that I can make a better decision.

The issue names no files, tests, or entry points. Start by locating the bench-deploy app-update flow and clarify which file changes and whether the update is a migrate or pull-only update; done means presenting actionable update details before deployment.

Written by the indexing model from the issue text.