feat: navigate to mailbox after successful mail import

- Add onSuccess prop to MailImportWizard, called instead of onClose on success
- MailDetailPage navigates to /mailpostfach after import completes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

paperless-frontend/src/components/MailImportWizard.tsx

@@ -18,11 +18,12 @@ const { Text } = Typography;
 interface MailImportWizardProps {
   visible: boolean;
   onClose: () => void;
+  onSuccess?: () => void;
   email: any;
   attachments: any[];
 }
 
-export default function MailImportWizard({ visible, onClose, email, attachments }: MailImportWizardProps) {
+export default function MailImportWizard({ visible, onClose, onSuccess, email, attachments }: MailImportWizardProps) {
   const [currentStep, setCurrentStep] = useState(0);
   const [importData, setImportData] = useState<AttachmentImportData[]>([]);
   const [loading, setLoading] = useState(false);
@@ -726,7 +727,7 @@ export default function MailImportWizard({ visible, onClose, email, attachments
       width={1000}
       footer={
         importSuccess ? (
-          <Button type="primary" onClick={onClose}>Schließen</Button>
+          <Button type="primary" onClick={onSuccess ?? onClose}>Schließen</Button>
         ) : (
           <Space>
             {currentStep > 0 && <Button onClick={handleBack}>Zurück</Button>}

paperless-frontend/src/pages/MailDetailPage.tsx

@@ -252,11 +252,12 @@ export default function MailDetailPage() {
       </div>
 
       {wizardOpen && email && (
-        <MailImportWizard 
-          visible={wizardOpen} 
-          onClose={() => setWizardOpen(false)} 
-          email={email} 
-          attachments={attachments} 
+        <MailImportWizard
+          visible={wizardOpen}
+          onClose={() => setWizardOpen(false)}
+          onSuccess={() => navigate('/mailpostfach')}
+          email={email}
+          attachments={attachments}
         />
       )}
     </div>