feat(i18n): localize backend messages by workspace language

web/src/app/home/components/workspace-settings/WorkspaceSettingsPanel.tsx

@@ -51,6 +51,17 @@ const ASSIGNABLE_ROLES: Exclude<WorkspaceRole, 'owner'>[] = [
   'viewer',
 ];
 
+const MESSAGE_LANGUAGES: Record<string, string> = {
+  en_US: 'English',
+  zh_Hans: '简体中文',
+  zh_Hant: '繁體中文',
+  ja_JP: '日本語',
+  es_ES: 'Español',
+  ru_RU: 'Русский',
+  th_TH: 'ไทย',
+  vi_VN: 'Tiếng Việt',
+};
+
 export default function WorkspaceSettingsPanel({
   active,
 }: WorkspaceSettingsPanelProps) {
@@ -61,6 +72,9 @@ export default function WorkspaceSettingsPanel({
   const [members, setMembers] = useState<WorkspaceMembership[]>([]);
   const [invitations, setInvitations] = useState<WorkspaceInvitation[]>([]);
   const [loading, setLoading] = useState(false);
+  const [messageLanguage, setMessageLanguage] = useState('en_US');
+  const [supportedLanguages, setSupportedLanguages] = useState<string[]>([]);
+  const [savingLanguage, setSavingLanguage] = useState(false);
   const [inviteEmail, setInviteEmail] = useState('');
   const [inviteRole, setInviteRole] =
     useState<Exclude<WorkspaceRole, 'owner'>>('viewer');
@@ -86,8 +100,13 @@ export default function WorkspaceSettingsPanel({
   const loadWorkspace = useCallback(async () => {
     setLoading(true);
     try {
-      const current = await backendClient.getCurrentWorkspace();
+      const [current, languageSettings] = await Promise.all([
+        backendClient.getCurrentWorkspace(),
+        backendClient.getWorkspaceLanguage(),
+      ]);
       setWorkspaceInfo(current);
+      setMessageLanguage(languageSettings.language);
+      setSupportedLanguages(languageSettings.supported_languages);
 
       const [memberResponse, invitationResponse] = await Promise.all([
         current.permissions.includes('member.view')
@@ -106,6 +125,19 @@ export default function WorkspaceSettingsPanel({
     }
   }, [t]);
 
+  async function saveLanguage(locale: string) {
+    setSavingLanguage(true);
+    try {
+      const result = await backendClient.setWorkspaceLanguage(locale);
+      setMessageLanguage(result.language);
+      toast.success(t('workspaceLanguage.saved'));
+    } catch {
+      toast.error(t('workspaceLanguage.saveFailed'));
+    } finally {
+      setSavingLanguage(false);
+    }
+  }
+
   useEffect(() => {
     if (active) void loadWorkspace();
   }, [active, loadWorkspace]);
@@ -222,6 +254,41 @@ export default function WorkspaceSettingsPanel({
       </PanelToolbar>
 
       <PanelBody className="space-y-6">
+        <section className="space-y-3">
+          <div>
+            <h3 id="workspace-language-label" className="text-sm font-semibold">
+              {t('workspaceLanguage.label')}
+            </h3>
+            <p
+              id="workspace-language-description"
+              className="text-xs text-muted-foreground"
+            >
+              {t('workspaceLanguage.description')}
+            </p>
+          </div>
+          <Select
+            value={messageLanguage}
+            onValueChange={saveLanguage}
+            disabled={
+              loading || savingLanguage || !permissions.has('workspace.update')
+            }
+          >
+            <SelectTrigger
+              className="w-full sm:w-64"
+              aria-labelledby="workspace-language-label"
+              aria-describedby="workspace-language-description"
+            >
+              <SelectValue />
+            </SelectTrigger>
+            <SelectContent>
+              {supportedLanguages.map((locale) => (
+                <SelectItem key={locale} value={locale}>
+                  {MESSAGE_LANGUAGES[locale] || locale}
+                </SelectItem>
+              ))}
+            </SelectContent>
+          </Select>
+        </section>
         {canInvite && (
           <section className="space-y-3">
             <div>

web/src/app/infra/http/BackendClient.ts

@@ -111,6 +111,17 @@ import type {
  * 负责与后端 API 的所有交互
  */
 export class BackendClient extends BaseHttpClient {
+  public getWorkspaceLanguage(): Promise<{
+    language: string;
+    supported_languages: string[];
+  }> {
+    return this.get('/api/v1/workspaces/current/language');
+  }
+
+  public setWorkspaceLanguage(language: string): Promise<{ language: string }> {
+    return this.put('/api/v1/workspaces/current/language', { language });
+  }
+
   constructor(baseURL: string) {
     super(baseURL, false);
   }

web/src/app/infra/http/BaseHttpClient.ts

@@ -11,6 +11,7 @@ import {
 } from './workspaceContext';
 import { setCurrentWorkspaceSnapshot } from './currentWorkspaceStore';
 import { clearWorkspaceBootstrapSnapshot } from './workspaceBootstrapStore';
+import i18n from 'i18next';
 
 type JSONValue = string | number | boolean | JSONObject | JSONArray | null;
 interface JSONObject {

web/src/i18n/locales/en-US.ts

@@ -1,6 +1,13 @@
 import slackSetup from './slack-setup/en-US';
 import pipelineMigration from './pipeline-migration/en-US';
 const enUS = {
+  workspaceLanguage: {
+    label: 'Workspace language',
+    description:
+      'Language for backend messages and default bot replies. Your interface language stays independent.',
+    saved: 'Language saved',
+    saveFailed: 'Failed to save language',
+  },
   slackSetup,
   inflight: {
     autoCollapse: 'Auto-collapse',

web/src/i18n/locales/es-ES.ts

@@ -1,5 +1,12 @@
 import pipelineMigration from './pipeline-migration/es-ES';
 const esES = {
+  workspaceLanguage: {
+    label: 'Idioma del espacio de trabajo',
+    description:
+      'Idioma de los mensajes del servidor y respuestas predeterminadas del bot. No cambia tu interfaz.',
+    saved: 'Idioma guardado',
+    saveFailed: 'No se pudo guardar el idioma',
+  },
   inflight: {
     autoCollapse: 'Plegar auto.',
     empty: 'No hay eventos en proceso',

web/src/i18n/locales/ja-JP.ts

@@ -1,6 +1,13 @@
 import slackSetup from './slack-setup/ja-JP';
 import pipelineMigration from './pipeline-migration/ja-JP';
 const jaJP = {
+  workspaceLanguage: {
+    label: 'ワークスペースの言語',
+    description:
+      'バックエンドの通知とボットの既定の返信に使用します。個人の表示言語には影響しません。',
+    saved: '言語設定を保存しました',
+    saveFailed: '言語設定の保存に失敗しました',
+  },
   slackSetup,
   inflight: {
     autoCollapse: '自動折りたたみ',

web/src/i18n/locales/ru-RU.ts

@@ -1,5 +1,12 @@
 import pipelineMigration from './pipeline-migration/ru-RU';
 const ruRU = {
+  workspaceLanguage: {
+    label: 'Язык рабочего пространства',
+    description:
+      'Язык сообщений сервера и стандартных ответов бота. Язык интерфейса не меняется.',
+    saved: 'Язык сохранён',
+    saveFailed: 'Не удалось сохранить язык',
+  },
   inflight: {
     autoCollapse: 'Автосворачивание',
     empty: 'Нет событий в обработке',

web/src/i18n/locales/th-TH.ts

@@ -1,5 +1,12 @@
 import pipelineMigration from './pipeline-migration/th-TH';
 const thTH = {
+  workspaceLanguage: {
+    label: 'ภาษาของพื้นที่ทำงาน',
+    description:
+      'ใช้สำหรับข้อความจากระบบและคำตอบเริ่มต้นของบอต โดยไม่เปลี่ยนภาษาอินเทอร์เฟซของคุณ',
+    saved: 'บันทึกภาษาแล้ว',
+    saveFailed: 'บันทึกภาษาไม่สำเร็จ',
+  },
   inflight: {
     autoCollapse: 'ยุบอัตโนมัติ',
     empty: 'ไม่มีเหตุการณ์ที่กำลังประมวลผล',

web/src/i18n/locales/vi-VN.ts

@@ -1,5 +1,12 @@
 import pipelineMigration from './pipeline-migration/vi-VN';
 const viVN = {
+  workspaceLanguage: {
+    label: 'Ngôn ngữ không gian làm việc',
+    description:
+      'Dùng cho thông báo máy chủ và phản hồi mặc định của bot. Không thay đổi ngôn ngữ giao diện cá nhân.',
+    saved: 'Đã lưu ngôn ngữ',
+    saveFailed: 'Không thể lưu ngôn ngữ',
+  },
   inflight: {
     autoCollapse: 'Tự thu gọn',
     empty: 'Không có sự kiện đang xử lý',

web/src/i18n/locales/zh-Hans.ts

@@ -1,6 +1,12 @@
 import slackSetup from './slack-setup/zh-Hans';
 import pipelineMigration from './pipeline-migration/zh-Hans';
 const zhHans = {
+  workspaceLanguage: {
+    label: '工作区语言',
+    description: '用于后端提示和机器人的默认回复，不影响个人界面语言。',
+    saved: '语言设置已保存',
+    saveFailed: '语言设置保存失败',
+  },
   slackSetup,
   inflight: {
     autoCollapse: '自动折叠',

web/src/i18n/locales/zh-Hant.ts

@@ -1,6 +1,12 @@
 import slackSetup from './slack-setup/zh-Hant';
 import pipelineMigration from './pipeline-migration/zh-Hant';
 const zhHant = {
+  workspaceLanguage: {
+    label: '工作區語言',
+    description: '用於後端提示和機器人的預設回覆，不影響個人介面語言。',
+    saved: '語言設定已儲存',
+    saveFailed: '語言設定儲存失敗',
+  },
   slackSetup,
   inflight: {
     autoCollapse: '自動摺疊',