feat(desktop): embed BoosAPI Desktop client as a subproject

Vendor the rebranded BoosAPI Desktop client (Tauri + Vue) into metapi as
a monorepo subdirectory under desktop/. Source only — node_modules,
dist, Cargo target and the upstream .git history are excluded.

desktop/ keeps its own independent Cargo workspace (desktop/src-tauri
with crates/*); it is not part of the backend boosapi crate, so a
`cargo check` at the metapi root still compiles only the backend. Build
the desktop app from desktop/src-tauri per desktop/README.md.

Note: app icons are still placeholder assets pending the final BoosAPI
logo. The updater signing keys live outside the repo and are not
included.

desktop/website/docs/zh/index.md

@@ -0,0 +1,57 @@
+---
+layout: home
+title: "BoosApi — 开源 AI 桌面客户端与网关"
+titleTemplate: false
+
+head:
+  - - meta
+    - name: description
+      content: "BoosApi 是免费开源的 AI 桌面客户端，支持多模型对话、Agent、MCP、ChatGPT/Cherry Studio/Kelivo 导入、本地知识库、S3/WebDAV 备份和内置 AI 网关。"
+
+hero:
+  name: BoosApi
+  text: "你的 AI 桌面工作台"
+  tagline: "多模型对话、Agent、MCP 工具、API 网关、数据导入、知识库和备份整合在一个本地优先客户端里"
+  image:
+    src: /logo.png
+    alt: BoosApi
+  actions:
+    - theme: brand
+      text: "快速开始"
+      link: /zh/guide/getting-started
+    - theme: alt
+      text: "下载"
+      link: /zh/download
+    - theme: alt
+      text: GitHub
+      link: https://github.com/BoosApi-Desktop/BoosApi
+
+features:
+  - icon: robot
+    title: "多模型对话"
+    details: "OpenAI、Claude、Gemini、DeepSeek、Qwen 和兼容 API，支持密钥轮询、分支、压缩和多模型回答。"
+  - icon: api
+    title: "服务商快速配置"
+    details: "boosapi:// 链接、CC Switch 导入、自定义请求头、代理、OpenAI Responses 和模型 extra_body。"
+  - icon: thunderbolt
+    title: "AI Agent"
+    details: "文件编辑、命令执行和代码分析，带权限分级、工作目录沙箱、审批 UI 和成本统计。"
+  - icon: edit
+    title: "富内容渲染"
+    details: "Markdown、LaTeX、Mermaid、D2、Monaco 代码块、HTML 片段和 Artifact 预览。"
+  - icon: search
+    title: "搜索与 RAG"
+    details: "带引用的联网搜索、查询生成、本地 sqlite-vec 知识库、重排设置和检索反馈。"
+  - icon: cloud-server
+    title: "API 网关"
+    details: "本地 OpenAI 兼容、OpenAI Responses、Claude 和 Gemini 接口，服务 Claude Code、Codex、OpenCode 等工具。"
+  - icon: book
+    title: "数据导入"
+    details: "导入 ChatGPT 官方导出、Cherry Studio 与 Kelivo 备份，处理重复并可迁移服务商。"
+  - icon: lock
+    title: "备份与安全"
+    details: "AES-256 本地加密、双目录数据布局、本地/WebDAV/S3 备份和恢复流程。"
+  - icon: desktop
+    title: "桌面体验"
+    details: "11 种界面语言、托盘、置顶、全局快捷键、开机自启、代理和自动更新检查。"
+---