Datenschutz vollmacht fixed, two time counter added

frontend/src/pages/customers/CustomerDetail.tsx

@@ -1,5 +1,6 @@
 import { useState, useEffect } from 'react';
 import { useParams, Link, useNavigate, useSearchParams, useLocation } from 'react-router-dom';
+import { pushHistory, popHistory } from '../../utils/navigation';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { customerApi, addressApi, bankCardApi, documentApi, meterApi, uploadApi, contractApi, stressfreiEmailApi, emailProviderApi, gdprApi, StressfreiEmail, ContractTreeNode } from '../../services/api';
 import { EmailClientTab } from '../../components/email';
@@ -22,7 +23,7 @@ export default function CustomerDetail({ portalCustomerId }: { portalCustomerId?
   const queryClient = useQueryClient();
   const { hasPermission, isCustomerPortal } = useAuth();
   const location = useLocation();
-  const backTo = (location.state as any)?.from as string | undefined;
+  const back = popHistory(location.state, isCustomerPortal ? '/' : '/customers');
   const [searchParams, setSearchParams] = useSearchParams();
   const customerId = portalCustomerId || parseInt(id!);
   const defaultTab = searchParams.get('tab') || 'addresses';
@@ -204,7 +205,7 @@ export default function CustomerDetail({ portalCustomerId }: { portalCustomerId?
     <div>
       <div className="flex items-center justify-between mb-6">
         <div className="flex items-center gap-3">
-          <Button variant="ghost" size="sm" onClick={() => navigate(backTo || (isCustomerPortal ? '/' : '/customers'))}>
+          <Button variant="ghost" size="sm" onClick={() => navigate(back.to, { state: back.state })}>
             <ArrowLeft className="w-4 h-4" />
           </Button>
           <div>
@@ -221,7 +222,7 @@ export default function CustomerDetail({ portalCustomerId }: { portalCustomerId?
         </div>
         <div className="flex gap-2">
           {hasPermission('customers:update') && (
-            <Link to={`/customers/${id}/edit`} state={{ from: `/customers/${id}` }}>
+            <Link to={`/customers/${id}/edit`} state={pushHistory(location.pathname + location.search, (location as any).state)}>
               <Button variant="secondary">
                 <Edit className="w-4 h-4 mr-2" />
                 Bearbeiten
@@ -649,7 +650,7 @@ function AddressesTab({
   const queryClient = useQueryClient();
   const deleteMutation = useMutation({
     mutationFn: addressApi.delete,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
   return (
@@ -746,18 +747,18 @@ function BankCardsTab({
   const updateMutation = useMutation({
     mutationFn: ({ id, data }: { id: number; data: Partial<BankCard> }) =>
       bankCardApi.update(id, data),
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
   const deleteMutation = useMutation({
     mutationFn: bankCardApi.delete,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
   const handleDocumentUpload = async (cardId: number, file: File) => {
     try {
       await uploadApi.uploadBankCardDocument(cardId, file);
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
     } catch (error) {
       console.error('Upload fehlgeschlagen:', error);
       alert('Upload fehlgeschlagen');
@@ -768,7 +769,7 @@ function BankCardsTab({
     if (!confirm('Dokument wirklich löschen?')) return;
     try {
       await uploadApi.deleteBankCardDocument(cardId);
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
     } catch (error) {
       console.error('Löschen fehlgeschlagen:', error);
       alert('Löschen fehlgeschlagen');
@@ -972,18 +973,18 @@ function DocumentsTab({
   const updateMutation = useMutation({
     mutationFn: ({ id, data }: { id: number; data: Partial<IdentityDocument> }) =>
       documentApi.update(id, data),
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
   const deleteMutation = useMutation({
     mutationFn: documentApi.delete,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
   const handleDocumentUpload = async (docId: number, file: File) => {
     try {
       await uploadApi.uploadIdentityDocument(docId, file);
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
     } catch (error) {
       console.error('Upload fehlgeschlagen:', error);
       alert('Upload fehlgeschlagen');
@@ -994,7 +995,7 @@ function DocumentsTab({
     if (!confirm('Dokument wirklich löschen?')) return;
     try {
       await uploadApi.deleteIdentityDocument(docId);
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
     } catch (error) {
       console.error('Löschen fehlgeschlagen:', error);
       alert('Löschen fehlgeschlagen');
@@ -1204,26 +1205,34 @@ function MetersTab({
   onAdd: () => void;
   onEdit: (meter: Meter) => void;
 }) {
-  const [showReadingModal, setShowReadingModal] = useState<{ meterId: number; meterType: 'ELECTRICITY' | 'GAS' } | null>(null);
+  const [showReadingModal, setShowReadingModal] = useState<{ meterId: number; meterType: 'ELECTRICITY' | 'GAS'; tariffModel?: string } | null>(null);
   const [expandedMeter, setExpandedMeter] = useState<number | null>(null);
-  const [editingReading, setEditingReading] = useState<{ meterId: number; meterType: 'ELECTRICITY' | 'GAS'; reading: any } | null>(null);
+  const [editingReading, setEditingReading] = useState<{ meterId: number; meterType: 'ELECTRICITY' | 'GAS'; tariffModel?: string; reading: any } | null>(null);
   const queryClient = useQueryClient();
 
   const updateMutation = useMutation({
     mutationFn: ({ id, data }: { id: number; data: Partial<Meter> }) =>
       meterApi.update(id, data),
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
+  const [deleteError, setDeleteError] = useState<string | null>(null);
+
   const deleteMutation = useMutation({
     mutationFn: meterApi.delete,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
+      setDeleteError(null);
+    },
+    onError: (err) => {
+      setDeleteError(err instanceof Error ? err.message : 'Fehler beim Löschen');
+    },
   });
 
   const deleteReadingMutation = useMutation({
     mutationFn: ({ meterId, readingId }: { meterId: number; readingId: number }) =>
       meterApi.deleteReading(meterId, readingId),
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
   const filtered = showInactive ? meters : meters.filter((m) => m.isActive);
@@ -1273,6 +1282,9 @@ function MetersTab({
                     <Badge variant={meter.type === 'ELECTRICITY' ? 'warning' : 'info'}>
                       {meter.type === 'ELECTRICITY' ? 'Strom' : 'Gas'}
                     </Badge>
+                    {meter.tariffModel === 'DUAL' && (
+                      <Badge variant="default">HT/NT</Badge>
+                    )}
                     {!meter.isActive && <Badge variant="danger">Inaktiv</Badge>}
                   </div>
                   {canEdit && (
@@ -1281,7 +1293,7 @@ function MetersTab({
                         <Button
                           variant="ghost"
                           size="sm"
-                          onClick={() => setShowReadingModal({ meterId: meter.id, meterType: meter.type })}
+                          onClick={() => setShowReadingModal({ meterId: meter.id, meterType: meter.type, tariffModel: meter.tariffModel })}
                           title="Zählerstand hinzufügen"
                         >
                           <Plus className="w-4 h-4" />
@@ -1371,14 +1383,17 @@ function MetersTab({
                           </span>
                           <div className="flex items-center gap-2">
                             <span className="font-mono flex items-center gap-1">
-                              {reading.value.toLocaleString('de-DE')} {reading.unit}
-                              <CopyButton value={reading.value.toString()} title="Nur Wert kopieren" />
-                              <CopyButton value={`${reading.value.toLocaleString('de-DE')} ${reading.unit}`} title="Mit Einheit kopieren" />
+                              {reading.valueNt !== undefined && reading.valueNt !== null ? (
+                                <>HT: {reading.value.toLocaleString('de-DE')} / NT: {reading.valueNt.toLocaleString('de-DE')} {reading.unit}</>
+                              ) : (
+                                <>{reading.value.toLocaleString('de-DE')} {reading.unit}</>
+                              )}
+                              <CopyButton value={reading.value.toString()} title="Wert kopieren" />
                             </span>
                             {canEdit && (
                               <div className="opacity-0 group-hover:opacity-100 flex gap-1">
                                 <button
-                                  onClick={() => setEditingReading({ meterId: meter.id, meterType: meter.type, reading })}
+                                  onClick={() => setEditingReading({ meterId: meter.id, meterType: meter.type, tariffModel: meter.tariffModel, reading })}
                                   className="text-gray-400 hover:text-blue-600"
                                   title="Bearbeiten"
                                 >
@@ -1417,6 +1432,7 @@ function MetersTab({
           onClose={() => setShowReadingModal(null)}
           meterId={showReadingModal.meterId}
           meterType={showReadingModal.meterType}
+          tariffModel={showReadingModal.tariffModel as any}
           customerId={customerId}
         />
       )}
@@ -1427,10 +1443,43 @@ function MetersTab({
           onClose={() => setEditingReading(null)}
           meterId={editingReading.meterId}
           meterType={editingReading.meterType}
+          tariffModel={editingReading.tariffModel as any}
           customerId={customerId}
           reading={editingReading.reading}
         />
       )}
+
+      {/* Fehler-Modal beim Löschen (z.B. Zähler noch an Vertrag) */}
+      {deleteError && (
+        <Modal isOpen={true} onClose={() => setDeleteError(null)} title="Zähler kann nicht gelöscht werden">
+          <p className="text-sm text-gray-600 mb-4">
+            Der Zähler ist noch folgenden Verträgen zugeordnet und kann daher nicht gelöscht werden:
+          </p>
+          <div className="space-y-2">
+            {deleteError.match(/[A-Z]+-[A-Z0-9]+/g)?.map((contractNumber) => (
+              <Link
+                key={contractNumber}
+                to={`/contracts?search=${contractNumber}`}
+                onClick={() => setDeleteError(null)}
+                className="flex items-center gap-2 p-3 bg-gray-50 border rounded-lg text-blue-600 hover:bg-blue-50 hover:border-blue-300 transition-colors"
+              >
+                <FileText className="w-4 h-4" />
+                <span className="font-mono">{contractNumber}</span>
+              </Link>
+            )) ?? (
+              <p className="text-sm text-red-600">{deleteError}</p>
+            )}
+          </div>
+          <p className="text-xs text-gray-500 mt-4">
+            Bitte entfernen Sie den Zähler zuerst aus den oben genannten Verträgen.
+          </p>
+          <div className="flex justify-end mt-4">
+            <Button variant="secondary" onClick={() => setDeleteError(null)}>
+              Schließen
+            </Button>
+          </div>
+        </Modal>
+      )}
     </div>
   );
 }
@@ -1457,7 +1506,7 @@ function ContractsTab({
   const deleteMutation = useMutation({
     mutationFn: contractApi.delete,
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       queryClient.invalidateQueries({ queryKey: ['customers'] });
       queryClient.invalidateQueries({ queryKey: ['contracts'] });
       queryClient.invalidateQueries({ queryKey: ['contract-tree', customerId] });
@@ -1549,7 +1598,7 @@ function ContractsTab({
                 <div className="w-6" /> // Platzhalter für Ausrichtung
               ) : null}
 
-              <Link to={`/contracts/${contract.id}`} state={{ from: `/customers/${customerId}?tab=contracts` }} className="font-mono flex items-center gap-1 text-blue-600 hover:underline">
+              <Link to={`/contracts/${contract.id}`} state={pushHistory(location.pathname + location.search, (location as any).state)} className="font-mono flex items-center gap-1 text-blue-600 hover:underline">
                 {contract.contractNumber}
                 <CopyButton value={contract.contractNumber} />
               </Link>
@@ -2054,7 +2103,7 @@ function AddressModal({
   const createMutation = useMutation({
     mutationFn: (data: typeof formData) => addressApi.create(customerId, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
       setFormData({
         type: 'DELIVERY_RESIDENCE',
@@ -2071,7 +2120,7 @@ function AddressModal({
   const updateMutation = useMutation({
     mutationFn: (data: typeof formData) => addressApi.update(address!.id, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
     },
   });
@@ -2201,7 +2250,7 @@ function BankCardModal({
   const createMutation = useMutation({
     mutationFn: (data: any) => bankCardApi.create(customerId, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
       setFormData({ accountHolder: '', iban: '', bic: '', bankName: '', expiryDate: '', isActive: true });
     },
@@ -2210,7 +2259,7 @@ function BankCardModal({
   const updateMutation = useMutation({
     mutationFn: (data: any) => bankCardApi.update(bankCard!.id, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
     },
   });
@@ -2333,7 +2382,7 @@ function DocumentModal({
   const createMutation = useMutation({
     mutationFn: (data: any) => documentApi.create(customerId, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
       setFormData({
         type: 'ID_CARD',
@@ -2351,7 +2400,7 @@ function DocumentModal({
   const updateMutation = useMutation({
     mutationFn: (data: any) => documentApi.update(document!.id, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
     },
   });
@@ -2498,6 +2547,7 @@ function MeterModal({
   const getInitialFormData = () => ({
     meterNumber: meter?.meterNumber || '',
     type: meter?.type || 'ELECTRICITY' as const,
+    tariffModel: meter?.tariffModel || 'SINGLE' as const,
     location: meter?.location || '',
     isActive: meter?.isActive ?? true,
   });
@@ -2507,16 +2557,16 @@ function MeterModal({
   const createMutation = useMutation({
     mutationFn: (data: any) => meterApi.create(customerId, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
-      setFormData({ meterNumber: '', type: 'ELECTRICITY', location: '', isActive: true });
+      setFormData({ meterNumber: '', type: 'ELECTRICITY', tariffModel: 'SINGLE', location: '', isActive: true });
     },
   });
 
   const updateMutation = useMutation({
     mutationFn: (data: any) => meterApi.update(meter!.id, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
     },
   });
@@ -2557,6 +2607,18 @@ function MeterModal({
           ]}
         />
 
+        {formData.type === 'ELECTRICITY' && (
+          <Select
+            label="Tarifmodell"
+            value={formData.tariffModel}
+            onChange={(e) => setFormData({ ...formData, tariffModel: e.target.value as any })}
+            options={[
+              { value: 'SINGLE', label: 'Eintarifzähler (Standard)' },
+              { value: 'DUAL', label: 'Zweitarifzähler (HT/NT)' },
+            ]}
+          />
+        )}
+
         <Input
           label="Standort"
           value={formData.location}
@@ -2594,6 +2656,7 @@ function MeterReadingModal({
   onClose,
   meterId,
   meterType,
+  tariffModel,
   customerId,
   reading,
 }: {
@@ -2601,47 +2664,63 @@ function MeterReadingModal({
   onClose: () => void;
   meterId: number;
   meterType: 'ELECTRICITY' | 'GAS';
+  tariffModel?: 'SINGLE' | 'DUAL';
   customerId: number;
-  reading?: { id: number; readingDate: string; value: number; unit: string; notes?: string } | null;
+  reading?: { id: number; readingDate: string; value: number; valueNt?: number; unit: string; notes?: string } | null;
 }) {
   const queryClient = useQueryClient();
   const isEditing = !!reading;
   const defaultUnit = meterType === 'ELECTRICITY' ? 'kWh' : 'm³';
+  const isDualTariff = tariffModel === 'DUAL';
 
   const getInitialFormData = () => ({
     readingDate: reading?.readingDate
       ? new Date(reading.readingDate).toISOString().split('T')[0]
       : new Date().toISOString().split('T')[0],
     value: reading?.value?.toString() || '',
+    valueNt: reading?.valueNt?.toString() || '',
     notes: reading?.notes || '',
   });
 
   const [formData, setFormData] = useState(getInitialFormData);
 
+  const [error, setError] = useState<string | null>(null);
+
   const createMutation = useMutation({
     mutationFn: (data: any) => meterApi.addReading(meterId, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
+      setError(null);
       onClose();
     },
+    onError: (err) => {
+      setError(err instanceof Error ? err.message : 'Fehler beim Speichern');
+    },
   });
 
   const updateMutation = useMutation({
     mutationFn: (data: any) => meterApi.updateReading(meterId, reading!.id, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
+      setError(null);
       onClose();
     },
+    onError: (err) => {
+      setError(err instanceof Error ? err.message : 'Fehler beim Speichern');
+    },
   });
 
   const handleSubmit = (e: React.FormEvent) => {
     e.preventDefault();
-    const data = {
+    const data: Record<string, unknown> = {
       readingDate: new Date(formData.readingDate),
       value: parseFloat(formData.value),
       unit: defaultUnit,
       notes: formData.notes || undefined,
     };
+    if (isDualTariff && formData.valueNt) {
+      data.valueNt = parseFloat(formData.valueNt);
+    }
     if (isEditing) {
       updateMutation.mutate(data);
     } else {
@@ -2667,10 +2746,10 @@ function MeterReadingModal({
           required
         />
 
-        <div className="grid grid-cols-3 gap-4">
-          <div className="col-span-2">
+        <div className={`grid ${isDualTariff ? 'grid-cols-2' : 'grid-cols-3'} gap-4`}>
+          <div className={isDualTariff ? '' : 'col-span-2'}>
             <Input
-              label="Zählerstand"
+              label={isDualTariff ? 'HT-Stand (Hochtarif)' : 'Zählerstand'}
               type="number"
               step="0.01"
               value={formData.value}
@@ -2678,12 +2757,26 @@ function MeterReadingModal({
               required
             />
           </div>
-          <div>
-            <label className="block text-sm font-medium text-gray-700 mb-1">Einheit</label>
-            <div className="h-10 flex items-center px-3 bg-gray-100 border border-gray-300 rounded-md text-gray-700">
-              {defaultUnit}
+          {isDualTariff && (
+            <div>
+              <Input
+                label="NT-Stand (Niedertarif)"
+                type="number"
+                step="0.01"
+                value={formData.valueNt}
+                onChange={(e) => setFormData({ ...formData, valueNt: e.target.value })}
+                required
+              />
             </div>
-          </div>
+          )}
+          {!isDualTariff && (
+            <div>
+              <label className="block text-sm font-medium text-gray-700 mb-1">Einheit</label>
+              <div className="h-10 flex items-center px-3 bg-gray-100 border border-gray-300 rounded-md text-gray-700">
+                {defaultUnit}
+              </div>
+            </div>
+          )}
         </div>
 
         <Input
@@ -2693,6 +2786,12 @@ function MeterReadingModal({
           placeholder="Optionale Notizen..."
         />
 
+        {error && (
+          <div className="p-3 bg-red-50 border border-red-200 rounded-lg text-sm text-red-700">
+            {error}
+          </div>
+        )}
+
         <div className="flex justify-end gap-2">
           <Button type="button" variant="secondary" onClick={onClose}>
             Abbrechen
@@ -2732,12 +2831,12 @@ function StressfreiEmailsTab({
   const updateMutation = useMutation({
     mutationFn: ({ id, data }: { id: number; data: Partial<StressfreiEmail> }) =>
       stressfreiEmailApi.update(id, data),
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
   const deleteMutation = useMutation({
     mutationFn: stressfreiEmailApi.delete,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['customer', customerId] }),
   });
 
   const filtered = showInactive ? emails : emails.filter((e) => e.isActive);
@@ -3087,7 +3186,7 @@ function StressfreiEmailModal({
       const result = await stressfreiEmailApi.enableMailbox(email.id);
       if (result.success) {
         setMailboxEnabled(true);
-        queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+        queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
         queryClient.invalidateQueries({ queryKey: ['mailbox-accounts', customerId] });
       } else {
         setProvisionError(result.error || 'Mailbox-Aktivierung fehlgeschlagen');
@@ -3108,7 +3207,7 @@ function StressfreiEmailModal({
         setMailboxEnabled(result.data.hasMailbox);
         if (result.data.wasUpdated) {
           // DB wurde aktualisiert, Query invalidieren
-          queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+          queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
         }
       }
     } catch (error) {
@@ -3199,7 +3298,7 @@ function StressfreiEmailModal({
       });
     },
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       queryClient.invalidateQueries({ queryKey: ['mailbox-accounts', customerId] });
       setLocalPart('');
       setNotes('');
@@ -3216,7 +3315,7 @@ function StressfreiEmailModal({
     mutationFn: (data: Partial<StressfreiEmail>) =>
       stressfreiEmailApi.update(email!.id, data),
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['customer', customerId.toString()] });
+      queryClient.invalidateQueries({ queryKey: ['customer', customerId] });
       onClose();
     },
   });
@@ -3664,6 +3763,7 @@ function ConsentTab({
     try {
       await uploadApi.uploadPrivacyPolicy(customerId, file);
       onUpdate?.();
+      queryClient.invalidateQueries({ queryKey: ['customer-consents', customerId] });
     } catch (error) {
       console.error('Upload fehlgeschlagen:', error);
       alert('Upload fehlgeschlagen');
@@ -3675,6 +3775,7 @@ function ConsentTab({
     try {
       await uploadApi.deletePrivacyPolicy(customerId);
       onUpdate?.();
+      queryClient.invalidateQueries({ queryKey: ['customer-consents', customerId] });
     } catch (error) {
       console.error('Löschen fehlgeschlagen:', error);
       alert('Löschen fehlgeschlagen');

frontend/src/pages/customers/CustomerForm.tsx

@@ -1,5 +1,6 @@
 import { useEffect } from 'react';
 import { useNavigate, useParams, useLocation } from 'react-router-dom';
+import { popHistory } from '../../utils/navigation';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useForm } from 'react-hook-form';
 import { customerApi } from '../../services/api';
@@ -17,7 +18,7 @@ export default function CustomerForm() {
   const location = useLocation();
   const queryClient = useQueryClient();
   const isEdit = !!id;
-  const backTo = (location.state as any)?.from as string | undefined;
+  const back = popHistory(location.state, isEdit ? `/customers/${id}` : '/customers');
 
   const { register, handleSubmit, reset, watch, setValue, formState: { errors } } = useForm<CustomerFormData>();
   const customerType = watch('type');
@@ -234,7 +235,7 @@ export default function CustomerForm() {
         </Card>
 
         <div className="flex justify-end gap-4">
-          <Button type="button" variant="secondary" onClick={() => navigate(backTo || (isEdit ? `/customers/${id}` : '/customers'))}>
+          <Button type="button" variant="secondary" onClick={() => navigate(back.to, { state: back.state })}>
             Abbrechen
           </Button>
           <Button type="submit" disabled={isLoading}>

frontend/src/pages/customers/CustomerList.tsx

@@ -1,6 +1,7 @@
 import { useState } from 'react';
 import { useQuery } from '@tanstack/react-query';
 import { Link } from 'react-router-dom';
+import { pushHistory } from '../../utils/navigation';
 import { customerApi } from '../../services/api';
 import { useAuth } from '../../context/AuthContext';
 import Card from '../../components/ui/Card';
@@ -78,12 +79,12 @@ export default function CustomerList() {
                   {data.data.map((customer) => (
                     <tr key={customer.id} className="border-b hover:bg-gray-50">
                       <td className="py-3 px-4 font-mono text-sm">
-                        <Link to={`/customers/${customer.id}`} state={{ from: '/customers' }} className="text-blue-600 hover:underline">
+                        <Link to={`/customers/${customer.id}`} state={pushHistory('/customers')} className="text-blue-600 hover:underline">
                           {customer.customerNumber}
                         </Link>
                       </td>
                       <td className="py-3 px-4">
-                        <Link to={`/customers/${customer.id}`} state={{ from: '/customers' }} className="text-blue-600 hover:underline">
+                        <Link to={`/customers/${customer.id}`} state={pushHistory('/customers')} className="text-blue-600 hover:underline">
                           {customer.type === 'BUSINESS' && customer.companyName
                             ? customer.companyName
                             : `${customer.firstName} ${customer.lastName}`}