Enhance pricing validation and update related components

- Added validation logic in `UpdatePricingSettingsCommandValidator` to ensure the annual price does not fall below the equivalent quarterly price, preventing potential pricing discrepancies.
- Updated `PricingSettings` model documentation to clarify that both pricing fields represent monthly rates, with calculations for total costs based on the number of months.
- Modified frontend components to reflect the new validation, including error messages when the annual price is cheaper than the quarterly price.
- Adjusted API documentation to accurately describe the pricing structure and validation rules for the pricing endpoints.

frontend/src/routes/admin/roles.tsx

@@ -20,8 +20,9 @@ function AdminRolesPage() {
   const { data, isLoading, isError, refetch } = useQuery({ queryKey: ['admin-roles'], queryFn: listRoles })
   const { data: pricing } = useQuery({ queryKey: ['admin-pricing'], queryFn: getPricingSettings })
 
-  const totalPrice = (price: number | null | undefined, maxConfigs: number) =>
-    price == null || maxConfigs < 0 ? t('admin.roles.noPrice') : `${price * maxConfigs} ₽`
+  // Ставки — цена за конфиг В МЕСЯЦ при данном тарифе; итог за период = ставка × месяцев × квота.
+  const totalPrice = (monthlyRate: number | null | undefined, maxConfigs: number, months: number) =>
+    monthlyRate == null || maxConfigs < 0 ? t('admin.roles.noPrice') : `${monthlyRate * months * maxConfigs} ₽`
 
   const deleteMutation = useMutation({
     mutationFn: deleteRole,
@@ -58,6 +59,7 @@ function AdminRolesPage() {
               <th className="py-2 font-medium">{t('admin.roles.maxConfigs')}</th>
               <th className="py-2 font-medium">{t('admin.roles.maxIpLimit')}</th>
               <th className="py-2 font-medium">{t('admin.roles.totalPerQuarter')}</th>
+              <th className="py-2 font-medium">{t('admin.roles.totalHalfYear')}</th>
               <th className="py-2 font-medium">{t('admin.roles.totalPerYear')}</th>
               <th className="py-2" />
               <th className="py-2" />
@@ -71,8 +73,9 @@ function AdminRolesPage() {
                 </td>
                 <td className="py-2">{role.maxConfigs < 0 ? t('unlimited') : role.maxConfigs}</td>
                 <td className="py-2">{role.maxIpLimit < 0 ? t('unlimited') : role.maxIpLimit}</td>
-                <td className="py-2">{totalPrice(pricing?.pricePerConfigPerQuarter, role.maxConfigs)}</td>
-                <td className="py-2">{totalPrice(pricing?.pricePerConfigPerYear, role.maxConfigs)}</td>
+                <td className="py-2">{totalPrice(pricing?.pricePerConfigPerQuarter, role.maxConfigs, 3)}</td>
+                <td className="py-2">{totalPrice(pricing?.pricePerConfigPerQuarter, role.maxConfigs, 6)}</td>
+                <td className="py-2">{totalPrice(pricing?.pricePerConfigPerYear, role.maxConfigs, 12)}</td>
                 <td className="py-2 text-right">
                   <Button size="sm" variant="outline" onClick={() => setEditing(role)}>
                     {t('admin.roles.edit')}