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>

pages/admin/sources.tsx

@@ -1,6 +1,7 @@
-import { useState, useEffect } from 'react'
+import { useState, useEffect, useCallback } from 'react'
 import type { NextPage } from 'next'
 import Head from 'next/head'
+import Link from 'next/link'
 
 interface Source {
   id: number
@@ -18,11 +19,7 @@ const SourcesManagement: NextPage = () => {
   const [loading, setLoading] = useState(true)
   const [filter, setFilter] = useState('pending')
 
-  useEffect(() => {
-    fetchSources()
-  }, [filter])
-
-  const fetchSources = async () => {
+  const fetchSources = useCallback(async () => {
     try {
       const response = await fetch(`/api/admin/sources?status=${filter}`)
       if (response.ok) {
@@ -34,7 +31,11 @@ const SourcesManagement: NextPage = () => {
     } finally {
       setLoading(false)
     }
-  }
+  }, [filter])
+
+  useEffect(() => {
+    fetchSources()
+  }, [fetchSources])
 
   const updateSource = async (id: number, status: string, riskLevel: number) => {
     try {
@@ -158,7 +159,7 @@ const SourcesManagement: NextPage = () => {
         )}
 
         <div style={{ marginTop: '30px' }}>
-          <a href="/admin" style={{ 
+          <Link href="/admin" style={{ 
             padding: '10px 20px', 
             backgroundColor: '#6b7280', 
             color: 'white', 
@@ -166,7 +167,7 @@ const SourcesManagement: NextPage = () => {
             borderRadius: '6px' 
           }}>
             ← Späť na dashboard
-          </a>
+          </Link>
         </div>
       </div>
     </div>

pages/api/sources/check.ts

@@ -76,7 +76,7 @@ export default async function handler(
       .split(',')
       .filter(Boolean)
 
-    const uniqueCategories = [...new Set(allCategories)]
+    const uniqueCategories = Array.from(new Set(allCategories))
 
     let message = ''
     if (maxRiskLevel >= 4) {