The review screen becomes the one diff screen from the approved design.
It walks the Changes section the file came from (uncommitted, staged or on
the branch) or one commit's files, so 'N of M' and next/previous stay in
that list. The title opens a jump-to-file sheet built on the shared
source-control tree, with search and viewed boxes. Unchanged runs fold the
way desktop's diff does. The bar's main button is Stage · next file for
uncommitted files and Viewed · next file otherwise; Discard and Unstage move
to the menu. Filter chips, hunk jumps and Stage Reviewed are gone.
openDiffForFile also takes { kind: 'commit', commitOid, filePath }, read
through git.commitCompare and git.commitDiff.