feat: task trash, triage trash and retention settings for every area; admin can forbid keeping things for good

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/workspace/TrashView.tsx

@@ -2,6 +2,7 @@ import React, { useState } from 'react';
 import { ArrowLeft, Folder, RotateCcw, Trash2 } from 'lucide-react';
 import { TrashedDocument } from '../../lib/types';
 import { CountBadge } from '../../components/CountBadge';
+import { formatDeletedAt } from '../../lib/due';
 
 interface TrashViewProps {
   items: TrashedDocument[];
@@ -12,12 +13,6 @@ interface TrashViewProps {
   onBackMobile: () => void;
 }
 
-const formatDeletedAt = (iso: string) => {
-  const d = new Date(iso);
-  if (Number.isNaN(d.getTime())) return '';
-  return d.toLocaleString('de-DE', { day: '2-digit', month: '2-digit', year: 'numeric', hour: '2-digit', minute: '2-digit' });
-};
-
 // Deleted notes: open read-only, restore, or delete for good. Deleting for good always takes a second
 // tap on the same button ("Wirklich löschen?"), which works the same with mouse and touch.
 export const TrashView: React.FC<TrashViewProps> = ({ items, onOpen, onRestore, onPurge, onEmpty, onBackMobile }) => {