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/features.md

@@ -0,0 +1,52 @@
+# Features
+
+BoosApi is a local-first AI desktop workspace. This page is updated for v0.0.85 and covers the recent provider import, third-party data import, MCP, HTML rendering, backup and gateway work.
+
+## Chat & Models
+
+- **Multi-provider chat** — Connect OpenAI, Claude, Gemini, DeepSeek, Qwen and any OpenAI-compatible endpoint with custom Base URL, API Path, headers and proxy rules.
+- **Provider onboarding** — Use boosapi:// provider links and CC Switch import to bring provider profiles into BoosApi after user confirmation.
+- **Model management** — Sync remote model lists, organize groups, test latency and configure capabilities, context length, sampling defaults, reasoning profiles and per-model extra_body fields.
+- **Conversation workflows** — Stream replies with thinking blocks, compare message versions, branch conversations, show title-generation status, compress long chats and ask multiple models in parallel.
+
+## AI Agent
+
+- **Agent mode** — Let the model read and edit files, run commands and analyze code inside a controlled desktop workflow.
+- **Permission control** — Choose standard review, auto-accept edits or full-access mode while keeping working-directory sandbox checks active.
+- **Approval and cost UI** — Review tool calls in real time, remember allow decisions and track token/cost usage for each agent session.
+
+## Content Rendering
+
+- **Markdown and math** — Render Markdown, code highlighting, tables, task lists and LaTeX formulas in streaming conversations.
+- **Code, diagrams and artifacts** — Use Monaco code blocks, Mermaid, D2 diagrams and an Artifact panel for code, Markdown notes, reports and previews.
+- **HTML fragment rendering** — Preview generated HTML fragments safely, including the streaming fixes added in the recent releases.
+
+## Search & Knowledge
+
+- **Web search** — Use Tavily, Zhipu WebSearch, Bocha and other search providers with cited sources and generated search queries.
+- **Local knowledge bases** — Index private documents with sqlite-vec, tune retrieval/rerank options and inspect retrieval feedback.
+- **Context management** — Attach files, search results, knowledge snippets, memories and tool output to the conversation context.
+
+## Tools & Extensions
+
+- **MCP protocol** — Run Model Context Protocol servers over stdio, SSE or StreamableHTTP.
+- **Built-in tools** — Use built-in MCP tools such as @boosapi/fetch and file search without installing a separate server.
+- **Tool loop limit** — Configure the maximum MCP tool-call loop count and recover more cleanly from interrupted or stuck tool sessions.
+
+## API Gateway
+
+- **Local gateway** — Expose OpenAI Chat Completions, OpenAI Responses, Claude-native and Gemini-native endpoints from the desktop app.
+- **Access and observability** — Manage gateway keys, SSL/TLS certificates, request logs and usage analytics locally.
+- **Client templates** — Use ready-made templates for Claude Code, Codex CLI, OpenCode, Gemini CLI and custom clients.
+
+## Data Import & Backup
+
+- **Third-party imports** — Import ChatGPT official exports, Cherry Studio backups and Kelivo backups with preview counts, warnings and duplicate handling.
+- **Provider and file migration** — Cherry Studio and Kelivo import can optionally migrate linked providers, API keys and file attachments.
+- **Backups** — Back up and restore local data through local folders, WebDAV or S3-compatible storage.
+
+## Desktop & Security
+
+- **Local encryption** — Store app state under ~/.boosapi/ and user files under ~/Documents/boosapi/, with API keys protected by AES-256 and a local master key.
+- **Desktop integration** — Use tray mode, always-on-top, global shortcuts, auto-start, proxy settings and automatic update checks.
+- **11 interface languages** — Switch between Simplified Chinese, Traditional Chinese, English, Japanese, Korean, French, German, Spanish, Russian, Hindi and Arabic.