[Feature Request] Shortcut to jump to next/prev changed hunk

When I'm doing a review I like to show full file context, but currently I have to manually scroll to every change. It would be great to have a keyboard shortcut to quickly jump to the next/previous change.

Start in the review UI's keyboard-shortcut handling and changed-hunk navigation entry points. Check how the current view identifies hunks, then verify that shortcuts move to the next and previous changes while preserving full-file context. Done means both directions work reliably during review.

Written by the indexing model from the issue text.