test(e2e): match the activity calendar on data attributes, not wording

The card carries data-period and each goal row and goal field a
data-goal-key, so the spec no longer depends on the English labels.

src/components/activity/__tests__/activity-calendar-card.test.tsx

@@ -140,6 +140,13 @@ describe("ActivityCalendarCard", () => {
     state.data = calendar();
     const html = render();
     expect(html).toContain("Steps per month");
+    // Stable hooks for the end-to-end spec, independent of the wording.
+    expect(html).toContain(
+      'data-slot="activity-calendar-goal" data-goal-key="stepsPerMonth"',
+    );
+    expect(html).toMatch(
+      /data-slot="activity-calendar"[^>]*data-period="month"/,
+    );
     expect(html).toContain(
       'data-slot="activity-calendar-week-goal" data-met="true"',
     );

src/components/activity/activity-calendar-card.tsx

@@ -173,6 +173,7 @@ export function ActivityCalendarCard() {
     <Card
       id="activity-calendar"
       data-slot="activity-calendar"
+      data-period={period}
       className="scroll-mt-28"
     >
       <CardHeader>
@@ -483,7 +484,12 @@ export function ActivityCalendarCard() {
 
             <div className="space-y-2" data-slot="activity-calendar-goals">
               {data.goalProgress.map((g) => (
-                <div key={g.key} className="space-y-1">
+                <div
+                  key={g.key}
+                  className="space-y-1"
+                  data-slot="activity-calendar-goal"
+                  data-goal-key={g.key}
+                >
                   <div className="flex items-center justify-between gap-3 text-sm">
                     <span className="inline-flex items-center gap-1.5">
                       <Target

src/components/activity/activity-goals-sheet.tsx

@@ -115,6 +115,7 @@ export function ActivityGoalsSheet({
               <Label htmlFor={id}>{t(`activityCalendar.goal.${key}`)}</Label>
               <Input
                 id={id}
+                data-goal-key={key}
                 inputMode="numeric"
                 autoComplete="off"
                 value={draft[key]}