feat(app): finalize 2.0 channel settings UI, 8-language alignment and cloud-sync groundwork

- 渠道设置界面：ChannelList/LlmProtocolFields/ProvidersSection 渠道级协议与模型配置
- 8 种界面语言 1711 项文案对齐（de/en/es/fr/ja/ko/zh-CN/zh-TW）
- Core 协议层 llm_protocol 与 provider_service 配套、云同步准备
- linux-egui 后端与 Android updater 配套调整

README.md

@@ -200,7 +200,7 @@ Every item below is one more layer sedimented into a default — a capability yo
 - **Toggle and push-to-talk** recording modes, plus a **MediaPlayPause trigger** so wired-earbud inline controls can start and stop recording. `Esc` cancels at any phase, including polish and insertion.
 - **Cloud ASR**: Volcengine streaming ASR (bigasr), iFlytek realtime ASR (RTASR), Alibaba Cloud Bailian (classic realtime / Qwen3 realtime / Fun-ASR-Flash file transcription), StepFun StepAudio (batch + realtime), Zhipu GLM-ASR, Xiaomi MiMo ASR, ElevenLabs Scribe, OpenAI-compatible batch transcription (OpenAI Whisper / Groq / SiliconFlow SenseVoice / OpenRouter / ZenMux), and Apple Speech (macOS).
 - **Local ASR**: bundled Qwen3-ASR (0.6B / 1.7B) via vendored `Open-Less/qwen-asr` (macOS); Windows Foundry Local Whisper and sherpa-onnx (experimental) variants.
-- **Polish providers**: Ark (Volcengine), DeepSeek, OpenAI, Google Gemini, Codex OAuth, SiliconFlow, Atlas Cloud, Xiaomi MiMo, CometAPI, OpenRouter, Alibaba Cloud Coding Plan, CodingPlanX, MiniMax, and StepFun — plus any OpenAI-compatible endpoint you bring.
+- **Polish providers**: Ark (Volcengine), DeepSeek, OpenAI, Google Gemini, Codex OAuth, SiliconFlow, Atlas Cloud, Xiaomi MiMo, CometAPI, OpenRouter, Alibaba Cloud Coding Plan, CodingPlanX, MiniMax, StepFun, and OpenCode Zen — plus any OpenAI-compatible endpoint you bring.
 - **Four output modes**: raw, light polish, structured (**AI-prompt mode**), and formal. Plus a **translation hotkey** that converts speech directly into the configured target language ([#43](../../issues/43)).
 - **Selection-ask QA panel** — a separate hotkey opens a floating panel that runs voice Q&A against the highlighted text in any app ([#118](../../issues/118)).
 - **Main window**: Overview / History / Vocab / Style / Marketplace / Settings. Persistent tray icon, plus a mini status capsule that floats on screen and follows the display you are typing on (multi-monitor).