feat: implement BackButton component for consistent navigation

- Added BackButton component to standardize back navigation across pages.
- Integrated BackButton into various pages, replacing custom back buttons for consistency.
- Updated PageHeader to accept backTo prop for displaying BackButton when navigating from subpages.
- Created useGoBack hook to handle navigation logic, determining whether to go back in history or redirect to a fallback page.
- Added tests for BackButton and its integration with PageHeader to ensure expected behavior.

assets/admin/pages/SecretaryDetailPage.tsx

@@ -69,7 +69,7 @@ export default function SecretaryDetailPage() {
         </Link>
       </div>
 
-      <PageHeader title={secretary.user_name} description="جزئیات منشی و سهم درآمد نوبت‌های آنلاین" />
+      <PageHeader backTo="/admin/secretaries" title={secretary.user_name} description="جزئیات منشی و سهم درآمد نوبت‌های آنلاین" />
 
       <div style={{ display: 'grid', gridTemplateColumns: 'repeat(auto-fit, minmax(300px, 1fr))', gap: 'var(--gap)' }}>
         <div className="card" style={{ padding: 20 }}>