feat: add mobile-responsive layout and card views across all pages

- New useIsMobile hook and MobileCardList component
- AppLayout: hamburger menu + Drawer navigation on mobile
- All list pages (Inbox, Posteingang, Manuell, Mail, Freigabe, Zahlung, TaskLog)
  show card layout on mobile instead of tables
- CSS: responsive modal height, horizontal table scroll, text-size-adjust
- Backend: Agrarmonitor polling fixes, Zahlung service improvements,
  IMAP folder service extended, misc controller fixes

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

paperless-frontend/src/components/DocumentSearchModal.tsx

@@ -57,7 +57,7 @@ export default function DocumentSearchModal({ open, onCancel, onSelect }: Props)
       open={open}
       onCancel={onCancel}
       footer={null}
-      width={800}
+      width={{ xs: '100vw', md: 800 }}
       style={{ top: 50 }}
     >
       <div style={{ marginBottom: 16 }}>
@@ -100,7 +100,7 @@ export default function DocumentSearchModal({ open, onCancel, onSelect }: Props)
                 description={
                   <Space direction="vertical" size={0}>
                     <Text type="secondary" style={{ fontSize: 12 }}>ID: {doc.id} | ASN: {doc.archive_serial_number || 'Keine'}</Text>
-                    <Text type="secondary" style={{ fontSize: 12 }}>Erstellt: {dayjs(doc.created_date).format('DD.MM.YYYY')}</Text>
+                    <Text type="secondary" style={{ fontSize: 12 }}>Erstellt: {dayjs(doc.created).format('DD.MM.YYYY')}</Text>
                   </Space>
                 }
               />