feat: Introduce cursor utility class for pointer interactions and refactor action buttons into PageHeaderActions component across multiple managers for improved UI consistency

frontend/src/BillingManager.jsx

@@ -683,64 +683,43 @@ function BillingManager() {
             <table className="table card-table table-vcenter table-nowrap mb-0">
               <thead>
                 <tr>
-                  <th 
-                    className="cursor-pointer"
-                    onClick={() => handleSort('hostName')}
-                  >
+                  <th className="cursor-pointer" onClick={() => handleSort('hostName')}>
                     Имя хостера
                     {sortField === 'hostName' && (
                       <span className="ms-1">{sortOrder === 'asc' ? '↑' : '↓'}</span>
                     )}
                   </th>
-                  <th 
-                    className="cursor-pointer"
-                    onClick={() => handleSort('purpose')}
-                  >
+                  <th className="cursor-pointer" onClick={() => handleSort('purpose')}>
                     Назначение
                     {sortField === 'purpose' && (
                       <span className="ms-1">{sortOrder === 'asc' ? '↑' : '↓'}</span>
                     )}
                   </th>
-                  <th 
-                    className="cursor-pointer"
-                    onClick={() => handleSort('country')}
-                  >
+                  <th className="cursor-pointer" onClick={() => handleSort('country')}>
                     Страна
                     {sortField === 'country' && (
                       <span className="ms-1">{sortOrder === 'asc' ? '↑' : '↓'}</span>
                     )}
                   </th>
-                  <th 
-                    className="cursor-pointer"
-                    onClick={() => handleSort('provider')}
-                  >
+                  <th className="cursor-pointer" onClick={() => handleSort('provider')}>
                     Провайдер
                     {sortField === 'provider' && (
                       <span className="ms-1">{sortOrder === 'asc' ? '↑' : '↓'}</span>
                     )}
                   </th>
-                  <th 
-                    className="cursor-pointer"
-                    onClick={() => handleSort('monthlyCost')}
-                  >
+                  <th className="cursor-pointer" onClick={() => handleSort('monthlyCost')}>
                     Месячная стоимость
                     {sortField === 'monthlyCost' && (
                       <span className="ms-1">{sortOrder === 'asc' ? '↑' : '↓'}</span>
                     )}
                   </th>
-                  <th 
-                    className="cursor-pointer"
-                    onClick={() => handleSort('nextPaymentDate')}
-                  >
+                  <th className="cursor-pointer" onClick={() => handleSort('nextPaymentDate')}>
                     Следующий платеж
                     {sortField === 'nextPaymentDate' && (
                       <span className="ms-1">{sortOrder === 'asc' ? '↑' : '↓'}</span>
                     )}
                   </th>
-                  <th 
-                    className="cursor-pointer"
-                    onClick={() => handleSort('status')}
-                  >
+                  <th className="cursor-pointer" onClick={() => handleSort('status')}>
                     Статус
                     {sortField === 'status' && (
                       <span className="ms-1">{sortOrder === 'asc' ? '↑' : '↓'}</span>