Support user override translation files for incomplete UI localization

What variant of Codex are you using?

Codex 26.422.30944 Windows 11

What feature would you like to see?

Codex already includes built-in localization, but in the current desktop build it is still incomplete: part of the interface is translated, while some menu items and settings remain in English. It would be very helpful to add a way for users to customize and extend translations without modifying the application’s internal files.

Possible solutions:

1. Support for a user localization file such as ru-RU.json or locale.override.json that is loaded on top of the built-in translations.
2. Support for a dedicated user localization folder such as ~/.codex/locales/, so translations can be stored and updated by language or by interface section.
3. Export of a localization template containing UI keys, English strings, current translations, and missing translations.
4. Import of user translations back into the app through Settings, without manual editing of internal resources.
5. A fallback mechanism for missing translations, so untranslated strings are automatically collected into a missing translations list.
6. The ability to use Codex itself to suggest and save translations into a user override file after user confirmation.
7. More consistent localization across all interface layers: application menus, settings, tooltips, system commands, and built-in sections.

Why this matters: full localization has a direct impact on usability, reduces cognitive load, lowers the chance of mistakes in settings, and makes the product more accessible for international users. For the company, this is also valuable in terms of user retention, trust in product quality, and faster localization improvements without having to wait for a full release just to fix a small number of strings.

The most practical model would be: official built-in localization + a user override layer + translation export/import support.

Additional information

_No response_