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/api/freigabe.ts

@@ -4,7 +4,6 @@ export interface FreigabeDocument {
   id: number;
   title: string;
   created: string;
-  created_date: string;
   correspondent: number | null;
   document_type: number | null;
   archive_serial_number: number | null;

paperless-frontend/src/api/zahlung.ts

@@ -6,7 +6,6 @@ export interface ZahlungDocument {
   id: number;
   title: string;
   created: string;
-  created_date: string;
   correspondent: number | null;
   document_type: number | null;
   archive_serial_number: number | null;