[Feature Request] Add i18n/L10n support for Chinese (Simplified) and other languages

Description

The Codex CLI desktop application (Electron-based, distributed as Windows AppX) currently has all UI text hardcoded in English, with no language switching option. As a Chinese-speaking user, I would like to request adding internationalization (i18n) / localization (l10n) support.

Motivation

• Many developers in China and other non-English-speaking regions would benefit from a localized interface
• Lowering the language barrier helps more developers adopt Codex
• The app is already bundled with Chromium-level zh-CN.pak locale files, so part of the infrastructure is already in place

Suggested Implementation

1. Extract all user-facing UI strings into a standard i18n framework
2. Provide a Chinese (Simplified, zh-CN) translation as the first non-English locale
3. Add a language switcher in the app settings
4. Detect system locale for default language

Additional Context

• Chromium .pak locale files for zh-CN already exist at app/locales/
• The main UI code is in app/resources/app.asar
• The manifest only declares en-US as a resource language
• Many Chinese users are interested in a localized Codex experience

Thank you for considering this feature! I'd be happy to help with translations if needed.