fix(dashboard): show a read failure on the Vorsorge tile, not an empty state

The tile already read the query's error flag but never branched on it, so
a failed reminder read fell through to "no upcoming checkup reminders" —
a missed preventive-care nudge hiding behind an honest-looking empty
state. Add a QueryErrorRow with retry before the empty check. Test
watched fail first against the fall-through.

src/components/measurement-reminders/__tests__/vorsorge-dashboard-card-error-state.test.tsx

@@ -0,0 +1,57 @@
+/**
+ * A reminder-read failure on the dashboard Vorsorge tile must not read as "no
+ * upcoming checkup reminders" — a missed preventive-care nudge is the harm
+ * behind that fall-through. `useMeasurementReminders` is forced into its error
+ * state; the tile has to render a `query-error-row` with retry and never the
+ * empty copy.
+ *
+ * SSR-static render; the query-backed hooks are mocked so the error branch is
+ * synchronous.
+ */
+import { describe, expect, it, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+
+vi.mock("@/hooks/use-measurement-reminders", () => ({
+  useMeasurementReminders: () => ({
+    data: undefined,
+    isError: true,
+    refetch: vi.fn(),
+  }),
+  useMeasurementReminderMutations: () => ({
+    satisfy: { mutate: vi.fn(), isPending: false },
+  }),
+}));
+
+vi.mock("@/hooks/use-encounters", () => ({
+  useEncounters: () => ({ data: { upcoming: [] } }),
+}));
+
+vi.mock("@/hooks/use-record-capabilities", () => ({
+  useRecordCapabilities: () => ({ canManage: true, canAdd: true }),
+}));
+
+vi.mock("next/navigation", () => ({
+  useRouter: () => ({ push: vi.fn(), replace: vi.fn() }),
+  usePathname: () => "/",
+  useSearchParams: () => new URLSearchParams(),
+}));
+
+import { I18nProvider } from "@/lib/i18n/context";
+import { VorsorgeDashboardCard } from "../vorsorge-dashboard-card";
+
+function render() {
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale="en">
+      <VorsorgeDashboardCard />
+    </I18nProvider>,
+  );
+}
+
+describe("<VorsorgeDashboardCard> — a read failure is honest, not empty", () => {
+  it("renders the query-error row with retry and never the empty copy", () => {
+    const html = render();
+    expect(html).toContain('data-slot="query-error-row"');
+    expect(html).toContain('data-slot="query-error-row-retry"');
+    expect(html).not.toContain("No upcoming checkup reminders");
+  });
+});

src/components/measurement-reminders/vorsorge-dashboard-card.tsx

@@ -32,6 +32,7 @@ import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { ListRow } from "@/components/ui/list-row";
+import { QueryErrorRow } from "@/components/ui/query-error-row";
 import { ResponsiveSheet } from "@/components/ui/responsive-sheet";
 import { Skeleton } from "@/components/ui/skeleton";
 import { MeasurementForm } from "@/components/measurements/measurement-form";
@@ -78,7 +79,7 @@ export function VorsorgeDashboardCard() {
   // the dashboard summary offering what the dedicated page withholds was the
   // tell that this row had never been asked.
   const { canManage } = useRecordCapabilities();
-  const { data: reminders, isError } = useMeasurementReminders();
+  const { data: reminders, isError, refetch } = useMeasurementReminders();
 
   // A query's `isLoading` is not a hydration-safe branch: TanStack reports the
   // optimistic mount fetch on the client's very first render and cannot on the
@@ -153,6 +154,10 @@ export function VorsorgeDashboardCard() {
               <Skeleton key={i} className="h-12 w-full" />
             ))}
           </div>
+        ) : isError ? (
+          // A read failure must not read as "no upcoming reminders" — a missed
+          // checkup is the harm behind that fall-through (§6).
+          <QueryErrorRow onRetry={() => refetch()} />
         ) : upcoming.length === 0 ? (
           <div className="space-y-2">
             <p className="text-muted-foreground text-sm">