feat: Replace anchor tags with button elements for close actions in multiple managers to improve accessibility and semantic HTML

frontend/src/ASNsNewManager.jsx

@@ -217,7 +217,7 @@ function ASNsNewManager() {
               {error}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setError('')}></a>
+          <button type="button" className="btn-close" onClick={() => setError('')}></button>
         </div>
       )}
       
@@ -231,7 +231,7 @@ function ASNsNewManager() {
               {success}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setSuccess('')}></a>
+          <button type="button" className="btn-close" onClick={() => setSuccess('')}></button>
         </div>
       )}
 

frontend/src/BillingManager.jsx

@@ -55,6 +55,8 @@ function BillingManager() {
     note: ''
   });
   const [editingPayment, setEditingPayment] = useState(null); // { serverId, index }
+  const [showDeletePaymentModal, setShowDeletePaymentModal] = useState(false);
+  const [paymentToDelete, setPaymentToDelete] = useState(null); // { serverId, index, data }
 
   // Состояние для курсов валют
   const [exchangeRates, setExchangeRates] = useState({
@@ -349,6 +351,36 @@ function BillingManager() {
     }
   }
 
+  // Удаление платежа из истории
+  const handleDeletePayment = () => {
+    if (!paymentToDelete || !paymentToDelete.serverId || paymentToDelete.index == null) {
+      setShowDeletePaymentModal(false);
+      return;
+    }
+    const { serverId, index } = paymentToDelete;
+    setBillingData(prev => prev.map(s => {
+      if (s.id !== serverId) return s;
+      const payments = Array.isArray(s.payments) ? [...s.payments] : [];
+      if (index >= 0 && index < payments.length) {
+        payments.splice(index, 1);
+      }
+      const last = payments
+        .slice()
+        .sort((a,b) => new Date(b.date) - new Date(a.date))[0];
+      return {
+        ...s,
+        payments,
+        lastPaymentDate: last?.date || '',
+        lastPaymentAmount: last?.amount || 0,
+        lastPaymentCurrency: last?.currency || s.monthlyCostCurrency || 'USD'
+      };
+    }));
+    setShowDeletePaymentModal(false);
+    setPaymentToDelete(null);
+    setSuccess('Платеж удалён');
+    setTimeout(() => setSuccess(''), 3000);
+  };
+
   function getCountryFlag(countryRaw) {
     if (!countryRaw) return '';
     const value = String(countryRaw).trim();
@@ -893,7 +925,7 @@ function BillingManager() {
         </div>
         <div className="card-body">
           <div className="table-responsive">
-            <table className="table table-vcenter">
+            <table className="table card-table table-vcenter table-nowrap mb-0">
               <thead>
                 <tr>
                   <th>Имя хостера</th>
@@ -954,6 +986,16 @@ function BillingManager() {
                           >
                             <IconEdit size={18} />
                           </button>
+                          <button
+                            className="btn btn-outline-danger btn-icon"
+                            title="Удалить платеж"
+                            onClick={() => {
+                              setPaymentToDelete({ serverId: r.server.id, index: r._index, data: r });
+                              setShowDeletePaymentModal(true);
+                            }}
+                          >
+                            <IconTrash size={18} />
+                          </button>
                         </div>
                       </td>
                     </tr>
@@ -1086,6 +1128,41 @@ function BillingManager() {
       }}
     />
   )}
+
+  {/* Модалка удаления платежа */}
+  {showDeletePaymentModal && (
+    <div className="modal show d-block" tabIndex="-1" style={{ backgroundColor: 'rgba(0,0,0,0.5)' }}>
+      <div className="modal-dialog">
+        <div className="modal-content">
+          <div className="modal-header">
+            <h5 className="modal-title">Удалить платеж</h5>
+            <button type="button" className="btn-close" onClick={() => setShowDeletePaymentModal(false)}></button>
+          </div>
+          <div className="modal-body">
+            <p>Вы уверены, что хотите удалить выбранный платеж?</p>
+            {paymentToDelete && (
+              <div className="alert alert-warning">
+                <div><strong>Сервер:</strong> {paymentToDelete.data?.server?.hostName}</div>
+                <div><strong>Дата:</strong> {formatDate(paymentToDelete.data?.date)}</div>
+                <div><strong>Сумма:</strong> {formatCurrency(paymentToDelete.data?.amount, paymentToDelete.data?.currency)}</div>
+                {paymentToDelete.data?.note && (
+                  <div><strong>Комментарий:</strong> {paymentToDelete.data?.note}</div>
+                )}
+              </div>
+            )}
+          </div>
+          <div className="modal-footer">
+            <button type="button" className="btn btn-secondary" onClick={() => setShowDeletePaymentModal(false)}>
+              Отмена
+            </button>
+            <button type="button" className="btn btn-danger" onClick={handleDeletePayment}>
+              Удалить
+            </button>
+          </div>
+        </div>
+      </div>
+    </div>
+  )}
     </div>
   );
 }

frontend/src/DataManager.jsx

@@ -190,7 +190,7 @@ function DataManager({ entityName, entityKey, placeholder }) {
               {error}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setError('')}></a>
+          <button type="button" className="btn-close" onClick={() => setError('')}></button>
         </div>
       )}
       
@@ -204,7 +204,7 @@ function DataManager({ entityName, entityKey, placeholder }) {
               {success}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setSuccess('')}></a>
+          <button type="button" className="btn-close" onClick={() => setSuccess('')}></button>
         </div>
       )}
 

frontend/src/DomainsNewManager.jsx

@@ -222,7 +222,7 @@ function DomainsNewManager() {
               {error}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setError('')}></a>
+          <button type="button" className="btn-close" onClick={() => setError('')}></button>
         </div>
       )}
       
@@ -236,7 +236,7 @@ function DomainsNewManager() {
               {success}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setSuccess('')}></a>
+          <button type="button" className="btn-close" onClick={() => setSuccess('')}></button>
         </div>
       )}
 

frontend/src/IPRangesManager.jsx

@@ -232,7 +232,7 @@ function IPRangesManager() {
               {error}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setError('')}></a>
+          <button type="button" className="btn-close" onClick={() => setError('')}></button>
         </div>
       )}
       
@@ -246,7 +246,7 @@ function IPRangesManager() {
               {success}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setSuccess('')}></a>
+          <button type="button" className="btn-close" onClick={() => setSuccess('')}></button>
         </div>
       )}
 

frontend/src/ServerManager.jsx

@@ -428,7 +428,7 @@ function ServerManager() {
               {error}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setError('')}></a>
+          <button type="button" className="btn-close" onClick={() => setError('')}></button>
         </div>
       )}
       
@@ -442,7 +442,7 @@ function ServerManager() {
               {success}
             </div>
           </div>
-          <a className="btn-close" onClick={() => setSuccess('')}></a>
+          <button type="button" className="btn-close" onClick={() => setSuccess('')}></button>
         </div>
       )}
 
@@ -760,9 +760,9 @@ function ServerManager() {
           <div className="card-header">
             <h3 className="card-title mb-0">Существующие связи ({connections.length})</h3>
           </div>
-          <div className="card-body">
-            <div className="table-responsive">
-              <table className="table table-vcenter">
+            <div className="card-body">
+              <div className="table-responsive">
+                <table className="table card-table table-vcenter table-nowrap mb-0">
                 <thead>
                   <tr>
                     <th>Сервер A</th>