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/ReserveAppointmentsPage.tsx

@@ -15,6 +15,7 @@ import AppointmentStatusDropdown from '../components/ui/AppointmentStatusDropdow
 import SearchableSelect from '../components/ui/SearchableSelect';
 import Pagination from '../components/ui/Pagination';
 import NewAppointmentDrawer from '../components/NewAppointmentDrawer';
+import BackButton from '../components/ui/BackButton';
 import { AppointmentInfoModal, TransferReserveModal } from '../components/AppointmentActions';
 
 const LIMIT = 20;
@@ -115,6 +116,9 @@ export default function ReserveAppointmentsPage() {
 
   return (
     <div className="fade-in" style={{ padding: '20px 24px' }}>
+      <div style={{ marginBottom: 14 }}>
+        <BackButton fallback="/admin/appointments" />
+      </div>
       <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', flexWrap: 'wrap', gap: 10, marginBottom: 16 }}>
         <h1 style={{ fontSize: 17, fontWeight: 800 }}>نوبت های رزرو شده</h1>
         <div style={{ display: 'flex', alignItems: 'center', gap: 8 }}>