🔧 fix: harden billing flow and sidebar settings

Add missing strings import for subscription fallback checks, log failed subscription refunds after retries, and extend sidebar module settings with a subscription management toggle plus translations.

web/src/pages/Setting/Personal/SettingsSidebarModulesUser.jsx

@@ -107,6 +107,7 @@ export default function SettingsSidebarModulesUser() {
         deployment: isSidebarModuleAllowed('admin', 'deployment'),
         redemption: isSidebarModuleAllowed('admin', 'redemption'),
         user: isSidebarModuleAllowed('admin', 'user'),
+        subscription: isSidebarModuleAllowed('admin', 'subscription'),
         setting: isSidebarModuleAllowed('admin', 'setting'),
       };
     }
@@ -344,6 +345,11 @@ export default function SettingsSidebarModulesUser() {
           title: t('模型部署'),
           description: t('模型部署管理'),
         },
+        {
+          key: 'subscription',
+          title: t('订阅管理'),
+          description: t('订阅套餐管理'),
+        },
         {
           key: 'redemption',
           title: t('兑换码管理'),