[Feature Request]: Support Simplified Chinese UI / i18n for Desktop app

[lidao2026-Coding]

Is your feature request related to a problem?

The Desktop GUI is English-only. DeepCode comes from HKU (a Chinese-speaking institution) and a large share of its users are Chinese speakers; the absence of a 简体中文 (Simplified Chinese) / 繁体中文 (Traditional Chinese) interface significantly hurts adoption and daily usability. (Note: the old web UI request in #79 was for the legacy web frontend and was closed the same day; this request is for the current v2.0 Tauri Desktop app.)

Describe the solution you'd like

Add proper i18n infrastructure to desktop/:

1. Introduce an i18n library (e.g. react-i18next / react-intl).
2. Move hardcoded UI strings in desktop/src/** into locale files.
3. Ship zh-CN and zh-TW (plus keep en) translations.
4. Follow system/OS language detection by default, with a manual override in Settings (Settings → Language).

Describe alternatives you've considered

• English-only is acceptable short-term, but a language switcher would significantly improve adoption in Chinese-speaking markets and among HKU/CN users.

Additional context

• No i18n dependencies exist in desktop/package.json today; UI strings are hardcoded in desktop/src/**.
• The CLI also prints English-only UI text; a shared locale for CLI+Desktop would be a plus.
• Version: DeepCode Desktop 0.1.0 (v2.0.0 runtime).

[Zongwei9888]

Thanks, and confirmed — we checked rather than assumed: there's no i18n dependency in desktop/package.json and the strings are hardcoded throughout. You're also right that #79 was about the old web UI and this is a separate request for the v2.0 desktop app.

This one we'll definitely do, but it needs its own effort. It's considerably larger than the other four — adding the framework, extracting every string, then keeping translations current as the UI evolves. Bundling it into the appearance work wouldn't have done it justice. Keeping this open and we'll pick it up properly.

Thanks again for all five reports — the versions, platform details and file paths made them quick to verify, and #153 in particular uncovered a problem well beyond DeepSeek.

[lidao2026-Coding]

Thanks for the quick turnaround on all five — great to see the appearance controls and the model-tier fixes land, and the i18n plan (#154) is genuinely appreciated.

For transparency: I've paused using the desktop app for now, so I can't verify hands-on — but the responsiveness and the thorough replies were very much appreciated. Best of luck with the roadmap!