feat(auth): enhance access control in PrivateRoute and display error message in LoginPage

assets/admin/pages/LoginPage.tsx

@@ -1,4 +1,5 @@
 import React, { useEffect, useRef, useState } from 'react';
+import { useSearchParams } from 'react-router-dom';
 import { toast } from 'sonner';
 import { EyeIcon, EyeSlashIcon } from '@heroicons/react/24/outline';
 import { useAuthStore } from '../stores/authStore';
@@ -10,6 +11,7 @@ type ForgotStep = 1 | 2 | 3;
 
 export default function LoginPage() {
   const login = useAuthStore((s) => s.login);
+  const [searchParams] = useSearchParams();
 
   const [mode, setMode]             = useState<Mode>('password');
   const [pwMobile, setPwMobile]     = useState('');
@@ -186,6 +188,17 @@ export default function LoginPage() {
           </p>
         </div>
 
+        {searchParams.get('error') === 'access_denied' && (
+          <div style={{
+            background: '#fee2e2', border: '1px solid #fca5a5',
+            borderRadius: 8, padding: '10px 14px',
+            fontSize: 13, color: '#dc2626', marginBottom: 16,
+            textAlign: 'center',
+          }}>
+            حساب شما دسترسی به پنل مدیریت را ندارد
+          </div>
+        )}
+
         {mode !== 'forgot' && (
           <div style={{ display: 'flex', gap: 4, marginBottom: 24, background: 'var(--bg-2)', borderRadius: 10, padding: 4 }}>
             {(['password', 'sms'] as const).map((m) => (