diff-review

# Diff review Spec §20.3 / §21.3.2: a code-migration / tune-collab handoff is worthless without a human-reviewable diff. This atom is the "present the patch, capture the decision" stage. ## Inputs - The project cwd's accumulated edits since the run started (or since the previous diff-review iteration). - `plan/steps.json` for context per file. ## Output ```text project-cwd/ └── review/ ├── diff.patch # unified diff (git apply-shaped) ├── summary.md # human-friendly per-file walkthrough ├── decision.json # { decision: 'accept' | 'reject' | 'partial', accepted_files: [...], rejected_files: [...], reviewer: 'user' | 'agent' } └── meta.json # { generatedAt, atomDigest, planRevision } ``` The atom raises a `choice` GenUI surface with the three top-level decisions (`accept` / `reject` / `partial`). On `partial` the user flips per-file decisions through follow-up surfaces. ## Convergence The atom completes when `decision.json` has a non-empty `decision`. Acceptance writes `handoffKind: 'patch'` (or `'deployable-app'` when a successful build-test is on file) into the eventual artifact manifest; rejection rolls back the patch via `git restore` or the equivalent in the `code-import`-bound repo path. ## Anti-patterns the prompt fragment forbids - Skipping the surface and assuming acceptance. - Generating a `decision.json` that lacks `accepted_files` / `rejected_files` on `partial` decisions. - Rolling back files outside `plan/steps.json`'s union of `files[]` — the patch boundary is a contract. ## Status Reserved id, prompt-only fragment in v1.