feat(i18n): add Japanese UI locale (日本語)

CONTRIBUTING.md

@@ -339,4 +339,51 @@ If you are contributing through a coding agent or remote environment, include th
 - Keep logs grep-friendly and avoid logging secrets, tokens, or full PII.
 - Follow ESLint, Prettier, and Rust formatting output as authoritative.
 
+### UI translations
+
+All locales use the same workflow. Use `useT()` for UI text and treat
+`app/src/lib/i18n/en.ts` as the key source. Preserve existing good translations,
+translate new or changed English meanings, and remove keys retired from English.
+`scripts/apply-i18n-translations.ts` applies translation JSON files, retains
+existing values, removes obsolete keys, and writes keys in English order. Supply
+real translations for new strings; its English fallback is not a finished translation.
+Run `pnpm i18n:check`, `pnpm i18n:english:check`, the i18n coverage test, and Prettier.
+Preserve interpolation placeholders exactly, including repeated placeholders and
+double braces. Keep product names, paths, commands, and technical identifiers intact.
+
+#### Japanese UI copy
+
+Review text where it appears: a button, setting label, status, empty state, or
+confirmation dialog. Prefer short action labels and plain, polite sentences.
+Remove roundabout wording, not information: keep conditions, units, upload
+destinations, consent requirements, and deletion scope. Errors should describe
+what happened without guessing a cause. For example, keep "no answer" distinct
+from "no data" or a connection failure.
+
+| Context | Prefer | Avoid |
+| --- | --- | --- |
+| Save button | 保存 | 変更内容の保存を実行 |
+| Saved status | 保存しました | 正常に保存されました |
+| Available action | 変更できます | 変更することができます |
+| Delete a stored memory item | メモリーから削除 | 忘れる |
+
+Use these terms consistently on the Memory screens. Translate by meaning rather
+than substituting words mechanically; source connections and answer citations are
+different concepts.
+
+| Concept | Japanese |
+| --- | --- |
+| Memory / memory engine | メモリー / メモリーエンジン |
+| Learning / preference | 学習内容 / 好み |
+| Brain / belief / memory pack | ブレイン / 信念 / メモリーパック |
+| Source to sync / answer citation | ソース / 出典 |
+| Context brief | コンテキスト要約; 要約 when the context is clear |
+| Sync / import | 同期 / インポート |
+| Endpoint URL / API key | 接続先URL / APIキー |
+| Conversation / thread / turn | 会話 / スレッド / ターン |
+
+Keep backend count units such as ターン; do not reinterpret them as messages or
+conversations. This is contributor writing guidance, not a separate Japanese key
+matcher, fallback, or validation rule.
+
 Thank you for contributing to OpenHuman.

app/src/components/LanguageSelect.test.tsx

@@ -0,0 +1,54 @@
+import { configureStore } from '@reduxjs/toolkit';
+import { fireEvent, render, screen } from '@testing-library/react';
+import { Provider } from 'react-redux';
+import { describe, expect, it } from 'vitest';
+
+import { I18nProvider, useT } from '../lib/i18n/I18nContext';
+import localeReducer, { setLocale } from '../store/localeSlice';
+import LanguageSelect from './LanguageSelect';
+
+function LanguageSetting() {
+  const { t } = useT();
+  return <span>{t('settings.language')}</span>;
+}
+
+function renderPicker() {
+  const store = configureStore({ reducer: { locale: localeReducer } });
+  store.dispatch(setLocale('en'));
+  render(
+    <Provider store={store}>
+      <I18nProvider>
+        <LanguageSelect />
+        <LanguageSetting />
+      </I18nProvider>
+    </Provider>
+  );
+  return store;
+}
+
+describe('LanguageSelect', () => {
+  it('offers Japanese in its native script and applies it immediately', () => {
+    const store = renderPicker();
+    expect(screen.getByRole('option', { name: '🇯🇵 日本語' })).toHaveValue('ja');
+
+    fireEvent.change(screen.getByRole('combobox'), { target: { value: 'ja' } });
+
+    expect(store.getState().locale.current).toBe('ja');
+    expect(screen.getByRole('combobox')).toHaveValue('ja');
+    expect(screen.getByText('言語')).toBeInTheDocument();
+    expect(document.documentElement.lang).toBe('ja');
+    expect(document.documentElement.dir).toBe('ltr');
+  });
+
+  it('can switch back to English after Japanese', () => {
+    const store = renderPicker();
+    const picker = screen.getByRole('combobox');
+    fireEvent.change(picker, { target: { value: 'ja' } });
+    fireEvent.change(picker, { target: { value: 'en' } });
+
+    expect(store.getState().locale.current).toBe('en');
+    expect(picker).toHaveValue('en');
+    expect(screen.getByText('Language')).toBeInTheDocument();
+    expect(document.documentElement.lang).toBe('en');
+  });
+});

app/src/components/LanguageSelect.tsx

@@ -13,6 +13,7 @@ interface LocaleOption {
 
 const LOCALE_OPTIONS: LocaleOption[] = [
   { value: 'en', flag: '🇬🇧', label: 'English' },
+  { value: 'ja', flag: '🇯🇵', label: '日本語' },
   { value: 'ko', flag: '🇰🇷', label: '한국어' },
   { value: 'zh-CN', flag: '🇨🇳', label: '简体中文' },
   { value: 'hi', flag: '🇮🇳', label: 'हिन्दी' },

app/src/components/settings/panels/__tests__/ComposioPanel.test.tsx

@@ -124,6 +124,28 @@ describe('ComposioPanel', () => {
     expect(screen.getByText(/Managed Composio auth is unavailable here/i)).toBeInTheDocument();
   });
 
+  test('renders the direct-only explanation in Japanese for a local session', async () => {
+    coreStateMock.mockReturnValue({ snapshot: { sessionToken: 'header.payload.local' } });
+    const Panel = await importPanel();
+    const { I18nProvider } = await import('../../../../lib/i18n/I18nContext');
+    renderWithProviders(
+      <I18nProvider>
+        <Panel embedded />
+      </I18nProvider>,
+      { preloadedState: { locale: { current: 'ja' } } }
+    );
+
+    expect(
+      await screen.findByText(
+        'この環境ではComposioのマネージド認証を利用できません。独自のComposio APIキーを入力するか、設定を後回しにしてください。'
+      )
+    ).toBeInTheDocument();
+    expect(screen.getByText('直接接続（独自のAPIキーを使用）')).toBeInTheDocument();
+    expect(
+      screen.queryByText(/Managed Composio auth is unavailable here/i)
+    ).not.toBeInTheDocument();
+  });
+
   test('saving Direct mode with a key calls setApiKey and masks the field', async () => {
     const Panel = await importPanel();
     renderWithProviders(<Panel />);

app/src/lib/i18n/I18nContext.tsx

@@ -10,6 +10,7 @@ import fr from './fr';
 import hi from './hi';
 import id from './id';
 import it from './it';
+import ja from './ja';
 import ko from './ko';
 import pl from './pl';
 import pt from './pt';
@@ -28,6 +29,7 @@ interface I18nContextValue {
 
 const translations: Record<Locale, Record<string, string>> = {
   en,
+  ja,
   ko,
   'zh-CN': zhCN,
   hi,

app/src/lib/i18n/__tests__/I18nContext.test.tsx

@@ -59,6 +59,18 @@ describe('I18nProvider', () => {
     expect(screen.getByTestId('missing-key')).toHaveTextContent('this.key.does.not.exist');
   });
 
+  it('serves Japanese translations with the existing unknown-key fallback', () => {
+    renderWithLocale('ja');
+
+    expect(screen.getByTestId('locale')).toHaveTextContent('ja');
+    expect(screen.getByText('言語')).toBeInTheDocument();
+    expect(screen.getByText('アプリデータを削除')).toBeInTheDocument();
+    expect(screen.getByText('終了')).toBeInTheDocument();
+    expect(screen.getByTestId('missing-key')).toHaveTextContent('this.key.does.not.exist');
+    expect(document.documentElement.lang).toBe('ja');
+    expect(document.documentElement.dir).toBe('ltr');
+  });
+
   it('serves German translations from the registered locale map', () => {
     renderWithLocale('de');
 

app/src/lib/i18n/__tests__/coverage.test.ts

@@ -14,6 +14,7 @@ const LOCALES = [
   'ru',
   'id',
   'it',
+  'ja',
   'ko',
   'pl',
 ] as const;
@@ -54,6 +55,19 @@ describe('i18n coverage', () => {
     expect(extra).toEqual([]);
   });
 
+  it('preserves Japanese interpolation placeholders exactly', () => {
+    const japanese = loadLocale('ja');
+    const placeholders = (value: string) => value.match(/\{+[^{}]+\}+/g)?.sort() ?? [];
+    const mismatches = Object.entries(enFlat)
+      .filter(
+        ([key, value]) =>
+          JSON.stringify(placeholders(japanese[key])) !== JSON.stringify(placeholders(value))
+      )
+      .map(([key]) => key);
+
+    expect(mismatches).toEqual([]);
+  });
+
   it.each(['en', ...LOCALES])('locale %s contains no em dashes', locale => {
     const flat = locale === 'en' ? enFlat : loadLocale(locale);
     const keysWithEmDashes = Object.entries(flat)

app/src/lib/i18n/__tests__/mascotDismissPath.test.ts

@@ -9,6 +9,7 @@ import fr from '../fr';
 import hi from '../hi';
 import id from '../id';
 import itIT from '../it';
+import ja from '../ja';
 import ko from '../ko';
 import pl from '../pl';
 import pt from '../pt';
@@ -25,6 +26,7 @@ const LOCALES: Record<string, Record<string, string>> = {
   hi,
   id,
   it: itIT,
+  ja,
   ko,
   pl,
   pt,

app/src/lib/i18n/ar.ts

@@ -3377,6 +3377,8 @@ const messages: TranslationMap = {
     'تكاملاتك الحالية (Gmail، Slack، GitHub، إلخ المرتبطة عبر OpenHuman) لن تكون مرئية: فهي موجودة في مستأجر Composio المُدار من OpenHuman.',
   'settings.composio.intro':
     'يُدمج Composio أكثر من 250 تطبيقًا خارجيًا كأدوات يمكن للوكيل استدعاؤها. اختر كيفية توجيه هذه الاستدعاءات.',
+  'settings.composio.directOnlyDesc':
+    'المصادقة المُدارة لـ Composio غير متاحة هنا. أدخل مفتاح API الخاص بك لـ Composio أو تخطَّ هذه الخطوة الآن.',
   'settings.composio.modeDirect': 'مباشر (استخدم مفتاح API الخاص بك)',
   'settings.composio.modeDirectDesc':
     'تذهب الاستدعاءات إلى backend.composio.dev مباشرةً. سيادي / مناسب للعمل دون اتصال. تنفيذ الأدوات يعمل بشكل متزامن؛ مشغّلات الـ webhooks الفورية لم تُوجَّه بعد في الوضع المباشر (مشكلة متابعة).',

app/src/lib/i18n/bn.ts

@@ -3435,6 +3435,8 @@ const messages: TranslationMap = {
     'OpenHuman-এর মাধ্যমে লিঙ্ক করা আপনার বিদ্যমান ইন্টিগ্রেশনগুলি (Gmail, Slack, GitHub ইত্যাদি) দৃশ্যমান হবে না: সেগুলি OpenHuman-পরিচালিত Composio টেন্যান্টে থাকে।',
   'settings.composio.intro':
     'Composio ২৫০+ বহিরাগত অ্যাপকে টুল হিসেবে ইন্টিগ্রেট করে যা আপনার এজেন্ট কল করতে পারে। এই টুল কলগুলি কীভাবে রুট হবে তা নির্বাচন করুন।',
+  'settings.composio.directOnlyDesc':
+    'এখানে Composio-এর পরিচালিত প্রমাণীকরণ উপলভ্য নয়। আপনার নিজের Composio API কী লিখুন অথবা আপাতত এই ধাপটি এড়িয়ে যান।',
   'settings.composio.modeDirect': 'ডাইরেক্ট (নিজের API কী আনুন)',
   'settings.composio.modeDirectDesc':
     'কলগুলি সরাসরি backend.composio.dev-এ যায়। সার্বভৌম / অফলাইন-বান্ধব। টুল এক্সিকিউশন সিঙ্ক্রোনাসভাবে কাজ করে; রিয়েল-টাইম ট্রিগার webhooks এখনও direct মোডে রুট করা হয় না (ফলো-আপ ইস্যু)।',

app/src/lib/i18n/de.ts

@@ -3526,6 +3526,8 @@ const messages: TranslationMap = {
     'Deine vorhandenen Integrationen (Gmail, Slack, GitHub usw., die über OpenHuman verknüpft sind) sind nicht sichtbar – sie befinden sich im von OpenHuman verwalteten Composio-Mandanten.',
   'settings.composio.intro':
     'Composio integriert mehr als 250 externe Apps als Tools, die dein Agent aufrufen kann. Wähle aus, wie diese Werkzeugaufrufe weitergeleitet werden.',
+  'settings.composio.directOnlyDesc':
+    'Die verwaltete Composio-Authentifizierung ist hier nicht verfügbar. Gib deinen eigenen Composio-API-Schlüssel ein oder überspringe diesen Schritt vorerst.',
   'settings.composio.modeDirect': 'Direkt (bring deinen eigenen API-Schlüssel mit)',
   'settings.composio.modeDirectDesc':
     'Anrufe gehen direkt an backend.composio.dev. Souverän / offlinefreundlich. Die Werkzeugausführung erfolgt synchron; Echtzeit-Trigger-Webhooks werden noch nicht im Direktmodus weitergeleitet (Folgeproblem).',

app/src/lib/i18n/en.ts

@@ -4018,6 +4018,8 @@ const en: TranslationMap = {
     "Your existing integrations (Gmail, Slack, GitHub, etc. linked through OpenHuman) won't be visible: they live in the OpenHuman-managed Composio tenant.",
   'settings.composio.intro':
     'Composio integrates 250+ external apps as tools your agent can call. Choose how those tool calls are routed.',
+  'settings.composio.directOnlyDesc':
+    'Managed Composio auth is unavailable here. Enter your own Composio API key or skip this for now.',
   'settings.composio.modeDirect': 'Direct (bring your own API key)',
   'settings.composio.modeDirectDesc':
     'Calls go to backend.composio.dev directly. Sovereign / offline-friendly. Tool execution works synchronously; real-time trigger webhooks are not yet routed in direct mode (follow-up issue).',

app/src/lib/i18n/es.ts

@@ -3489,6 +3489,8 @@ const messages: TranslationMap = {
     'Tus integraciones existentes (Gmail, Slack, GitHub, etc. vinculadas a través de OpenHuman) no serán visibles: viven en el inquilino de Composio gestionado por OpenHuman.',
   'settings.composio.intro':
     'Composio integra más de 250 aplicaciones externas como herramientas que tu agente puede invocar. Elige cómo se enrutan esas llamadas.',
+  'settings.composio.directOnlyDesc':
+    'La autenticación administrada de Composio no está disponible aquí. Introduce tu propia clave API de Composio u omite este paso por ahora.',
   'settings.composio.modeDirect': 'Directo (usa tu propia clave API)',
   'settings.composio.modeDirectDesc':
     'Las llamadas van directamente a backend.composio.dev. Soberano / amigable con uso sin conexión. La ejecución de herramientas funciona de forma síncrona; los webhooks de triggers en tiempo real aún no están enrutados en modo directo (incidencia pendiente).',

app/src/lib/i18n/fr.ts

@@ -3505,6 +3505,8 @@ const messages: TranslationMap = {
     'Vos intégrations existantes (Gmail, Slack, GitHub, etc. liées via OpenHuman) ne seront pas visibles: elles vivent dans le tenant Composio géré par OpenHuman.',
   'settings.composio.intro':
     "Composio intègre plus de 250 applications externes en tant qu'outils que votre agent peut appeler. Choisissez comment ces appels d'outils sont routés.",
+  'settings.composio.directOnlyDesc':
+    'L’authentification gérée de Composio n’est pas disponible ici. Saisis ta propre clé API Composio ou passe cette étape pour le moment.',
   'settings.composio.modeDirect': 'Direct (apporte ta propre clé API)',
   'settings.composio.modeDirectDesc':
     "Les appels vont directement à backend.composio.dev. Souverain / compatible hors ligne. L'exécution des outils fonctionne de manière synchrone ; les webhooks de déclencheurs en temps réel ne sont pas encore routés en mode direct (problème de suivi).",

app/src/lib/i18n/hi.ts

@@ -3436,6 +3436,8 @@ const messages: TranslationMap = {
     'आपके मौजूदा एकीकरण (Gmail, Slack, GitHub, आदि OpenHuman के माध्यम से लिंक किए गए) दिखाई नहीं देंगे: वे OpenHuman-प्रबंधित Composio टेनेंट में रहते हैं।',
   'settings.composio.intro':
     'Composio 250+ बाहरी ऐप्स को टूल्स के रूप में एकीकृत करता है जिन्हें आपका एजेंट कॉल कर सकता है। चुनें कि वे टूल कॉल कैसे रूट किए जाएँ।',
+  'settings.composio.directOnlyDesc':
+    'यहाँ Composio का प्रबंधित प्रमाणीकरण उपलब्ध नहीं है। अपनी Composio API कुंजी दर्ज करें या अभी यह चरण छोड़ दें।',
   'settings.composio.modeDirect': 'डायरेक्ट (अपनी API key लाएं)',
   'settings.composio.modeDirectDesc':
     'कॉल सीधे backend.composio.dev पर जाती हैं। संप्रभु / ऑफ़लाइन-अनुकूल। टूल निष्पादन सिंक्रोनस रूप से कार्य करता है; रीयल-टाइम ट्रिगर वेबहुक्स अभी डायरेक्ट मोड में रूट नहीं हैं (फॉलो-अप मुद्दा)।',

app/src/lib/i18n/id.ts

@@ -3459,6 +3459,8 @@ const messages: TranslationMap = {
     'Integrasi Anda yang sudah ada (Gmail, Slack, GitHub, dll. yang terhubung melalui OpenHuman) tidak akan terlihat: mereka berada di tenant Composio yang dikelola OpenHuman.',
   'settings.composio.intro':
     'Composio mengintegrasikan 250+ aplikasi eksternal sebagai tool yang dapat dipanggil agen Anda. Pilih cara pemanggilan tool tersebut dirutekan.',
+  'settings.composio.directOnlyDesc':
+    'Autentikasi Composio terkelola tidak tersedia di sini. Masukkan kunci API Composio Anda sendiri atau lewati langkah ini untuk sementara.',
   'settings.composio.modeDirect': 'Langsung (bawa API key Anda sendiri)',
   'settings.composio.modeDirectDesc':
     'Panggilan langsung ke backend.composio.dev. Berdaulat / ramah offline. Eksekusi tool berjalan sinkron; webhook trigger real-time belum dirutekan dalam mode direct (isu lanjutan).',

app/src/lib/i18n/it.ts

@@ -3486,6 +3486,8 @@ const messages: TranslationMap = {
     'Le tue integrazioni esistenti (Gmail, Slack, GitHub, ecc. collegate tramite OpenHuman) non saranno visibili: risiedono nel tenant Composio gestito da OpenHuman.',
   'settings.composio.intro':
     'Composio integra oltre 250 app esterne come strumenti che il tuo agente può chiamare. Scegli come instradare queste chiamate.',
+  'settings.composio.directOnlyDesc':
+    'L’autenticazione gestita di Composio non è disponibile qui. Inserisci la tua chiave API Composio o salta questo passaggio per ora.',
   'settings.composio.modeDirect': 'Diretta (usa la tua chiave API)',
   'settings.composio.modeDirectDesc':
     "Le chiamate vanno direttamente a backend.composio.dev. Sovrana / offline-friendly. L'esecuzione degli strumenti funziona in modo sincrono; i webhook dei trigger in tempo reale non sono ancora instradati in modalità diretta (issue di follow-up).",