feat: 添加 RustDesk 协议支持和项目文档

- 新增 RustDesk 模块，支持与 RustDesk 客户端连接
  - 实现会合服务器协议和 P2P 连接
  - 支持 NaCl 加密和密钥交换
  - 添加视频帧和 HID 事件适配器
- 添加 Protobuf 协议定义 (message.proto, rendezvous.proto)
- 新增完整项目文档
  - 各功能模块文档 (video, hid, msd, otg, webrtc 等)
  - hwcodec 和 RustDesk 协议技术报告
  - 系统架构和技术栈文档
- 更新 Web 前端 RustDesk 配置界面和 API

Cargo.toml

@@ -113,6 +113,11 @@ gpio-cdev = "0.6"
 # H264 hardware/software encoding (hwcodec from rustdesk)
 hwcodec = { path = "libs/hwcodec" }
 
+# RustDesk protocol support
+prost = "0.13"
+sodiumoxide = "0.2"
+sha2 = "0.10"
+
 # High-performance pixel format conversion (libyuv)
 libyuv = { path = "res/vcpkg/libyuv" }
 
@@ -123,6 +128,9 @@ typeshare = "1.0"
 tokio-test = "0.4"
 tempfile = "3"
 
+[build-dependencies]
+prost-build = "0.13"
+
 [profile.release]
 opt-level = 3
 lto = true