Own changes to a contributor's pull request wait for approval

When the agent reviewing a contributor's pull request fixes a finding itself, its commits and the text that goes with them now stay on the card until the owner approves the demo. The pull request block shows what will go out, and the approve button says what it does: push and merge, push only, or push and send the requests to the contributor as one review. Requests decided together with own changes travel in the same message, so the contributor hears once and does not work on a branch that is pushed to later. If the contributor pushes in between, nothing goes out and the agent rebuilds its change on the new head.