Fix live test follow-up issues

src/app/dashboard/notdienst/notdienst-form.tsx

@@ -1,13 +1,14 @@
 "use client";
 
 import { useState, useTransition } from "react";
+import { useRouter } from "next/navigation";
 import { Info, Loader2, CheckCircle2 } from "lucide-react";
 import { format } from "date-fns";
 import { de } from "date-fns/locale";
 import { toast } from "sonner";
 
 import { cn } from "@/lib/utils";
-import { getWorkingDaysOfMonth } from "@/lib/date-utils";
+import { formatDateKey, getWorkingDaysOfMonth } from "@/lib/date-utils";
 import { Button } from "@/components/ui/button";
 import { saveNotdienstAvailabilities } from "./actions";
 
@@ -23,7 +24,7 @@ interface NotdienstFormProps {
   targetMonth: number;
   isLocked: boolean;
   requiredDaysTotal: number;
-  initialSelectedDates: string[]; // ISO Strings
+  initialSelectedDates: string[];
   childrenIds: string[];
 }
 
@@ -35,7 +36,8 @@ export function NotdienstForm({
   initialSelectedDates,
   childrenIds,
 }: NotdienstFormProps) {
-  // Lokaler State für die Auswahl. Ein Datum liegt immer als ISO-String vor (z.B. "2026-06-01T00:00:00.000Z")
+  const router = useRouter();
+  // Lokaler State für die Auswahl. Ein Datum liegt als stabiler yyyy-MM-dd-Schlüssel vor.
   const [selectedDates, setSelectedDates] = useState<Set<string>>(
     new Set(initialSelectedDates),
   );
@@ -78,7 +80,9 @@ export function NotdienstForm({
       if (result?.error) {
         toast.error(result.error);
       } else {
+        setSelectedDates(new Set(result.dates));
         toast.success("Verfügbarkeiten erfolgreich gespeichert.");
+        router.refresh();
       }
     });
   }
@@ -134,7 +138,7 @@ export function NotdienstForm({
         </div>
         <div className="divide-y">
           {workingDays.map((day) => {
-            const dateStr = day.toISOString();
+            const dateStr = formatDateKey(day);
             const isSelected = selectedDates.has(dateStr);
             const isToday = day.getTime() === new Date().setHours(0, 0, 0, 0);