i18n

# Desktop i18n Keep localization organized as: ```text apps/desktop/ ├── plugins/static-i18n-plugin.ts └── src/i18n/ ├── I18nRoot.tsx ├── runtime.ts ├── store.ts ├── generated/catalog.json └── locales/ ├── zh-CN.json └── en-US.json ``` ## Author messages - Use the global `t()` function with a static Simplified Chinese string literal: `t("保存")`. - Do not import or locally declare `t`. - Keep calls inside render paths when the result must update after a language change. Do not translate module-level UI constants. - Use named placeholders with a static object: `t("第 {page} 页", { page })`. - Preserve every placeholder name exactly in all translations. - Wrap all user-visible labels, descriptions, tooltips, empty states, validation messages, and accessibility labels. Do not wrap protocol tokens, model IDs, URLs, or product names that should remain unchanged. ## Locale behavior - `system` is the default preference. - Resolve supported operating-system languages to their locale and fall back to `en-US` for every unsupported language. - Persist only explicit locale selections. Removing the preference restores system-language behavior. - Apply changes immediately and update the document `lang` attribute. ## Update catalogs From `apps/desktop`: 1. Run `npm run i18n:scan` after adding or changing `t()` sources. 2. Translate every empty entry in `src/i18n/locales/en-US.json`. 3. Never edit `src/i18n/generated/catalog.json` or `zh-CN.json` manually; scanning owns them. 4. Run `npm run check`. A normal build must fail on a missing translation or mismatched placeholder. When adding another locale, add it to the plugin's supported locales, runtime locale type and messages, locale resolver, settings options, and provide a complete locale JSON file.