Admin: Letzte Aktivität pro User (nur echte Aktionen, kein Polling)

backend/src/routes/admin.js

@@ -31,7 +31,7 @@ router.post('/restore', authenticate, requireAdmin, upload.single('database'), (
 
 // GET /api/admin/users – alle Benutzer mit Statistiken
 router.get('/users', authenticate, requireAdmin, (req, res) => {
-  const users = db.prepare("SELECT id, username, role, created_at FROM users ORDER BY role DESC, username").all();
+  const users = db.prepare("SELECT id, username, role, created_at, last_active_at FROM users ORDER BY role DESC, username").all();
   const stats = users.map(u => {
     const archiv     = db.prepare('SELECT COUNT(*) c FROM calculations WHERE user_id=?').get(u.id).c;
     const bestellung = db.prepare('SELECT COUNT(*) c FROM orders WHERE user_id=?').get(u.id).c;