fix(frontend): comprehensive i18n cleanup and Select component hardening

frontend/src/i18n/locales/en.ts

@@ -145,11 +145,13 @@ export default {
     copiedToClipboard: 'Copied to clipboard',
     copyFailed: 'Failed to copy',
     contactSupport: 'Contact Support',
-    selectOption: 'Select an option',
-    searchPlaceholder: 'Search...',
-    noOptionsFound: 'No options found',
-    saving: 'Saving...',
-    refresh: 'Refresh',
+        selectOption: 'Select an option',
+        searchPlaceholder: 'Search...', 
+        noOptionsFound: 'No options found',
+        noGroupsAvailable: 'No groups available',
+        unknownError: 'Unknown error occurred',
+        saving: 'Saving...', 
+        selectedCount: '({count} selected)',    refresh: 'Refresh',
     notAvailable: 'N/A',
     now: 'Now',
     unknown: 'Unknown',
@@ -687,6 +689,10 @@ export default {
       failedToWithdraw: 'Failed to withdraw',
       useDepositWithdrawButtons: 'Please use deposit/withdraw buttons to adjust balance',
       insufficientBalance: 'Insufficient balance, balance cannot be negative after withdrawal',
+      roles: {
+        admin: 'Admin',
+        user: 'User'
+      },
       // Settings Dropdowns
       filterSettings: 'Filter Settings',
       columnSettings: 'Column Settings',

frontend/src/i18n/locales/zh.ts

@@ -145,7 +145,10 @@ export default {
     selectOption: '请选择',
     searchPlaceholder: '搜索...',
     noOptionsFound: '无匹配选项',
+    noGroupsAvailable: '无可用分组',
+    unknownError: '发生未知错误',
     saving: '保存中...',
+    selectedCount: '（已选 {count} 个）',
     refresh: '刷新',
     notAvailable: '不可用',
     now: '现在',
@@ -679,10 +682,6 @@ export default {
         admin: '管理员',
         user: '用户'
       },
-      statuses: {
-        active: '正常',
-        banned: '禁用'
-      },
       form: {
         emailLabel: '邮箱',
         emailPlaceholder: '请输入邮箱',