fix(workouts): read a day with activity data and no workout as rest

The strain run writes no impulse row on a day without a scorable workout
or active energy, so a rest day for someone without daily active energy
was never rated: fitness and fatigue held for months instead of
decaying, and the figures named the last stored day while the coverage
count ended there too.

A day without a stored impulse is now classified from the underlying
data: a workout on the day leaves it unrated, steps, heart rate or
active energy without a workout make it rest, and no data at all leaves
it unrated. The series runs to the day the strain run scores, so a
stretch without data after the last rated day shows in the coverage
count, and the card names the last rated day when it lies further back
than the day before.

src/components/workouts/__tests__/training-load-card.test.tsx

@@ -44,7 +44,19 @@ describe("<TrainingLoadCard>", () => {
   it("says how many recent days were rated when some were not", () => {
     const html = render({ ...OK, recentRatedDays: 25, recentDays: 42 });
     expect(html).toContain('data-slot="training-load-coverage"');
-    expect(html).toContain("25 of the last 42 days have heart-rate data");
+    expect(html).toContain("25 of the last 42 days could be rated");
+  });
+
+  it("names the last rated day when it lies behind the series end", () => {
+    const series = [
+      { day: "2026-10-19", ctl: 54, atl: 61, tsb: -7, rated: false },
+      { day: "2026-10-20", ctl: 54, atl: 61, tsb: -7, rated: false },
+    ];
+    const stale = render({ ...OK, asOf: "2026-09-02", series });
+    expect(stale).toContain('data-slot="training-load-as-of"');
+    expect(stale).toMatch(/As of 0?9\/0?2|As of 02\/09|As of Sep/);
+    const fresh = render({ ...OK, asOf: "2026-10-19", series });
+    expect(fresh).not.toContain('data-slot="training-load-as-of"');
   });
 
   it("signs a positive form and drops the warm-up note once covered", () => {

src/components/workouts/training-load-card.tsx

@@ -6,11 +6,14 @@ import { Card, CardContent, CardHeader } from "@/components/ui/card";
 import { TileHeader } from "@/components/insights/tile-header";
 import { useFormatters, useTranslations } from "@/lib/i18n/context";
 import type { TrainingLoad } from "@/lib/insights/training-load";
+import { shiftDateKey } from "@/lib/tz/format";
 
 /**
  * v1.44 — fitness, fatigue and form from the stored training impulse, the
  * server's figures as given. Renders nothing until the model has 28 days and
- * three training days to stand on.
+ * three training days to stand on. The series ends on the day the strain run
+ * scores; when the last rated day lies more than a day before that, the card
+ * names it, so figures held through weeks without data never pass as fresh.
  */
 export function TrainingLoadCard({
   trainingLoad,
@@ -21,6 +24,10 @@ export function TrainingLoadCard({
   const fmt = useFormatters();
   if (!trainingLoad || trainingLoad.status !== "ok") return null;
 
+  const seriesEnd = trainingLoad.series.at(-1)?.day;
+  const stale =
+    seriesEnd !== undefined && trainingLoad.asOf < shiftDateKey(seriesEnd, -1);
+
   const stats = [
     { key: "fitness", value: trainingLoad.ctl },
     { key: "fatigue", value: trainingLoad.atl },
@@ -47,6 +54,16 @@ export function TrainingLoadCard({
           ))}
         </dl>
         <p className="text-sm">{t("insights.workouts.load.explainer")}</p>
+        {stale ? (
+          <p
+            className="text-muted-foreground text-xs"
+            data-slot="training-load-as-of"
+          >
+            {t("insights.workouts.load.asOf", {
+              date: fmt.dateShortSmartCalendar(trainingLoad.asOf),
+            })}
+          </p>
+        ) : null}
         {trainingLoad.recentRatedDays < trainingLoad.recentDays ? (
           <p
             className="text-muted-foreground text-xs"