feat(reminders): preventive-care surface — wann, was, wo

Add the Vorsorge page and section: an upcoming-reminders list sorted by
server-computed next-due, with a create form (measurement-linked or
free-text, cadence, notify hour, location) and a per-card Erledigt and
delete action. Cards stay neutral-coloured regardless of due state — the
status reads through a discreet badge only, never an alarming tint. Copy
ships in all six locales.

src/hooks/use-measurement-reminders.ts

@@ -0,0 +1,97 @@
+"use client";
+
+/**
+ * v1.17.1 — data hook for Vorsorge (measurement) reminders.
+ *
+ * Wraps the `/api/measurement-reminders` CRUD + satisfy surface behind
+ * TanStack Query. Every mutation invalidates the one
+ * `measurementReminders()` root so the section list and the dashboard
+ * tile repaint in lockstep. The DTO is the server-authoritative shape —
+ * the client renders `nextDueAt` as-is, never recomputing.
+ */
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+
+import { apiDelete, apiGet, apiPatch, apiPost } from "@/lib/api/api-fetch";
+import { queryKeys } from "@/lib/query-keys";
+
+export interface MeasurementReminder {
+  id: string;
+  label: string;
+  measurementType: string | null;
+  intervalDays: number | null;
+  rrule: string | null;
+  anchorDate: string | null;
+  notifyHour: number;
+  location: string | null;
+  nextDueAt: string | null;
+  lastSatisfiedAt: string | null;
+  enabled: boolean;
+  createdAt: string;
+  updatedAt: string;
+}
+
+export interface CreateMeasurementReminderBody {
+  label: string;
+  measurementType?: string | null;
+  intervalDays?: number | null;
+  rrule?: string | null;
+  anchorDate?: string | null;
+  notifyHour?: number;
+  location?: string | null;
+  enabled?: boolean;
+}
+
+export type UpdateMeasurementReminderBody = Partial<
+  CreateMeasurementReminderBody
+>;
+
+const BASE = "/api/measurement-reminders";
+
+export function useMeasurementReminders(enabled = true) {
+  return useQuery({
+    queryKey: queryKeys.measurementReminders(),
+    queryFn: () => apiGet<MeasurementReminder[]>(BASE),
+    enabled,
+  });
+}
+
+export function useMeasurementReminderMutations() {
+  const qc = useQueryClient();
+  const invalidate = () =>
+    qc.invalidateQueries({ queryKey: queryKeys.measurementReminders() });
+
+  const create = useMutation({
+    mutationKey: queryKeys.measurementReminderCreate(),
+    mutationFn: (body: CreateMeasurementReminderBody) =>
+      apiPost<MeasurementReminder>(BASE, body),
+    onSuccess: invalidate,
+  });
+
+  const update = useMutation({
+    mutationKey: queryKeys.measurementReminderUpdate(),
+    mutationFn: ({
+      id,
+      body,
+    }: {
+      id: string;
+      body: UpdateMeasurementReminderBody;
+    }) => apiPatch<MeasurementReminder>(`${BASE}/${id}`, body),
+    onSuccess: invalidate,
+  });
+
+  const remove = useMutation({
+    mutationKey: queryKeys.measurementReminderDelete(),
+    mutationFn: (id: string) =>
+      apiDelete<{ deleted: boolean }>(`${BASE}/${id}`),
+    onSuccess: invalidate,
+  });
+
+  const satisfy = useMutation({
+    mutationKey: queryKeys.measurementReminderSatisfy(),
+    mutationFn: (id: string) =>
+      apiPost<MeasurementReminder>(`${BASE}/${id}/satisfy`),
+    onSuccess: invalidate,
+  });
+
+  return { create, update, remove, satisfy };
+}