## Motivation

Iterative refinements to the newly-merged Review Surface v2 so it better matches the original concept against real data — tracked in [DEV-10667](https://linear.app/whalesync/issue/DEV-10667-review-surface-v2-phase-7b-refine-new-ui).

## Change description

- **ReviewSubbar**: replaced the filter pills with `All` / `Pending` / `Problems`, renamed "By type" → "By field" (disabled when nothing is pending), and ported the column picker from `FolderDataGrid`.
- **ReviewTableGrid**: honors `visibleColumnIds` (defaults to just the changed columns + title while a review filter is active), fades non-title cells on deleted rows, and draws a sort-direction caret on the sorted column's header.
- **RecordReviewDrawer** (renamed from `RecordChangesDrawer`): 50% wider, a bottom `Changes` / `All fields` toggle (persists across record navigation; defaults to All fields for a record with no changes), and per-field approve/reject that shares extracted helpers (`applyAcceptedFieldChangeToOpenRecordData`, `deriveRowStatusAfterEdit`) with `RecordDetailView`.
- **scratch-git-2 / scratchmd**: new `pending` filter op (`approvedChanges = 1 OR unapprovedChanges = 1`) plus a folder-wide `pending_changes` summary count, wired through `scratchmd` → `local-files` → the renderer so the Pending pill pages and counts folder-wide (covered by a new `folder_index` unit test).

## Checklists

- [x] Security impact of change has been considered
- Data Incident Risk: 
    - [x] None
    - [ ] Low
    - [ ] High