feat: Implement date formatting utility functions and update components to use formatted timestamps for improved readability and consistency across the application.

frontend/src/Dashboard.jsx

@@ -1,6 +1,7 @@
 import { useState, useEffect } from 'react';
 import { Link } from 'react-router-dom';
 import api from './lib/api.js';
+import { formatDateTime } from './lib/datetime.js';
 import {
   IconWorld,
   IconNetwork,
@@ -130,7 +131,7 @@ function Dashboard() {
         // Получаем дату последнего обновления
           // Новый формат: объект с ключами { domainsNew, asns, servers, filters, ipRanges }
           const lmRaw = s3Res.status === 'fulfilled' ? s3Res.value.data?.domainsNew?.lastModified : null;
-          const lastModified = lmRaw ? new Date(lmRaw).toLocaleString() : new Date().toLocaleString();
+          const lastModified = lmRaw ? formatDateTime(lmRaw) : formatDateTime(new Date());
 
         const domainsCount = domainsRes.status === 'fulfilled' && typeof domainsRes.value.data?.total === 'number'
           ? domainsRes.value.data.total