Show expected vs actual pace/HR per lap in the Review Queue

Activities recorded from a structured Garmin workout carry a workoutId;
when its steps line up 1:1 with the recorded laps, the per-step target
pace/HR zone is resolved (via a Karvonen lookup for named zones) and stored
on each lap. The Review Queue plots it against the actual per-lap pace/HR
so the user can eyeball whether a run matches its plan while sorting it.

frontend/src/pages/ReviewQueue.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useMemo, useState } from "react";
 import { api } from "../api/client";
+import { ExpectedVsActualChart } from "../components/charts/ExpectedVsActualChart";
 import type { ReviewQueueItem, ScoredKind, WorkoutKind } from "../types/api";
 
 const UNSORTED = "__unsorted__";
@@ -129,6 +130,8 @@ export function ReviewQueue() {
                   </p>
                 )}
 
+                <ExpectedVsActualChart laps={item.laps} />
+
                 <div className="review-item-actions">
                   {manuallyAssignableKinds.map((k) => (
                     <button