feat: add local diff review workflow

src/main.rs

@@ -82,6 +82,11 @@ Diff: :diff (Normal); choose Before then After; Working checkout After edits liv
       Esc closes Before/After selectors; :diff.close exits an opened comparison explicitly
       Remote refs/history load into temporary comparison repos without changing active refs/checkout
       Changed files: normal picker/explorer bindings, Ctrl+w close; A/M/D/R status and rename paths
+Local reviews: :diff.comment at caret; use palette or Visual binding for a selected line range
+      :diff.review.edit/delete [ID], :diff.review.next/previous, :diff.review.overview
+      :diff.review.summary; :diff.review.verdict looks_good|changes_requested|none
+      :diff.review.save PATH / :diff.review.open PATH; :w in review panes saves local JSON
+      Snapshot anchors stay immutable; stale comments lose gutter markers; no publishing
 Pull requests: :pull_requests [REMOTE]; GitHub/GitLab/Gitea Open/Closed/All tabs, type to search
       Enter opens the immutable PR head against its merge base; API auth uses provider tokens or gh/glab
 Resolve jj conflicts: :resolve opens the current working-copy conflicts in a dedicated workspace