fix(app): stabilize diff reviews and workspace tabs

Reuse measured diff geometry when review controls open, keeping the interaction responsive on large changes. Preserve complete tab-track snapshots while exact content widths settle so new tabs and retained workspaces do not flash or truncate.

packages/app/src/git/diff-document/surface.native.tsx

@@ -93,7 +93,6 @@ export function DiffSurface(props: DiffSurfaceProps) {
       typography,
       measurement,
       props.palette,
-      reviewActions,
       t,
     ] as const;
     const previous = reusableModelRef.current;