Fix admin panel authentication and navigation for static export

- Replace router.push with window.location.href for reliable redirects
- Fix auth check to wait for component mount before accessing localStorage
- Ensure proper redirect after successful login
- Fix redirect behavior on all admin pages (dashboard, colors, requests)

app/upadaj/colors/page.tsx

@@ -53,13 +53,16 @@ export default function ColorsManagement() {
 
   // Check authentication
   useEffect(() => {
+    // Wait for component to mount to avoid SSR issues with localStorage
+    if (!mounted) return;
+
     const token = localStorage.getItem('authToken');
     const expiry = localStorage.getItem('tokenExpiry');
 
     if (!token || !expiry || Date.now() > parseInt(expiry)) {
-      router.push('/upadaj');
+      window.location.href = '/upadaj';
     }
-  }, [router]);
+  }, [mounted]);
 
   // Fetch colors
   const fetchColors = async () => {

app/upadaj/dashboard/page.tsx

@@ -123,13 +123,16 @@ export default function AdminDashboard() {
 
   // Check authentication
   useEffect(() => {
+    // Wait for component to mount to avoid SSR issues with localStorage
+    if (!mounted) return;
+
     const token = localStorage.getItem('authToken');
     const expiry = localStorage.getItem('tokenExpiry');
 
     if (!token || !expiry || Date.now() > parseInt(expiry)) {
-      router.push('/upadaj');
+      window.location.href = '/upadaj';
     }
-  }, [router]);
+  }, [mounted]);
 
   // Fetch filaments
   const fetchFilaments = async () => {

app/upadaj/page.tsx

@@ -32,8 +32,8 @@ export default function AdminLogin() {
       // Track successful login
       trackEvent('Admin', 'Login', 'Success');
 
-      // Redirect to admin dashboard
-      router.push('/upadaj/dashboard');
+      // Redirect to admin dashboard using window.location for static export
+      window.location.href = '/upadaj/dashboard';
     } catch (err: any) {
       setError('Neispravno korisničko ime ili lozinka');
       console.error('Login error:', err);

app/upadaj/requests/page.tsx

@@ -42,7 +42,7 @@ export default function ColorRequestsAdmin() {
     const expiry = localStorage.getItem('tokenExpiry');
 
     if (!token || !expiry || new Date().getTime() > parseInt(expiry)) {
-      router.push('/upadaj');
+      window.location.href = '/upadaj';
     }
   };