fix build issues

pages/admin/index.tsx

@@ -1,6 +1,7 @@
 import { useState, useEffect } from 'react'
 import type { NextPage } from 'next'
 import Head from 'next/head'
+import Link from 'next/link'
 
 interface DashboardStats {
   total_sources: number
@@ -90,7 +91,7 @@ const AdminDashboard: NextPage = () => {
         <div style={{ marginTop: '40px' }}>
           <h2>Rýchle akcie</h2>
           <div style={{ display: 'flex', gap: '15px', marginTop: '20px' }}>
-            <a href="/admin/sources" style={{ 
+            <Link href="/admin/sources" style={{ 
               padding: '12px 24px', 
               backgroundColor: '#3b82f6', 
               color: 'white', 
@@ -98,8 +99,8 @@ const AdminDashboard: NextPage = () => {
               borderRadius: '6px' 
             }}>
               Správa zdrojov
-            </a>
-            <a href="/admin/reports" style={{ 
+            </Link>
+            <Link href="/admin/reports" style={{ 
               padding: '12px 24px', 
               backgroundColor: '#10b981', 
               color: 'white', 
@@ -107,7 +108,7 @@ const AdminDashboard: NextPage = () => {
               borderRadius: '6px' 
             }}>
               Hlásenia
-            </a>
+            </Link>
           </div>
         </div>
       </div>