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

docs/modules/events.md

@@ -0,0 +1,353 @@
+# Events 模块文档
+
+## 1. 模块概述
+
+Events 模块提供事件总线功能，用于模块间通信和状态广播。
+
+### 1.1 主要功能
+
+- 事件发布/订阅
+- 多订阅者广播
+- WebSocket 事件推送
+- 状态变更通知
+
+### 1.2 文件结构
+
+```
+src/events/
+└── mod.rs              # EventBus 实现
+```
+
+---
+
+## 2. 架构设计
+
+```
+┌─────────────────────────────────────────────────────────────────────────────┐
+│                          Event System                                        │
+└─────────────────────────────────────────────────────────────────────────────┘
+
+┌────────────────┐ ┌────────────────┐ ┌────────────────┐
+│     Video      │ │      HID       │ │     Audio      │
+│    Module      │ │    Module      │ │    Module      │
+└───────┬────────┘ └───────┬────────┘ └───────┬────────┘
+        │                  │                  │
+        │   publish()      │   publish()      │   publish()
+        └──────────────────┼──────────────────┘
+                           │
+                           ▼
+                ┌─────────────────────┐
+                │      EventBus       │
+                │ (broadcast channel) │
+                └──────────┬──────────┘
+                           │
+         ┌─────────────────┼─────────────────┐
+         │                 │                 │
+         │   subscribe()   │   subscribe()   │
+         ▼                 ▼                 ▼
+┌────────────────┐ ┌────────────────┐ ┌────────────────┐
+│   WebSocket    │ │   DeviceInfo   │ │   Internal     │
+│   Handler      │ │  Broadcaster   │ │    Tasks       │
+└────────────────┘ └────────────────┘ └────────────────┘
+```
+
+---
+
+## 3. 核心组件
+
+### 3.1 EventBus
+
+```rust
+pub struct EventBus {
+    /// 广播发送器
+    tx: broadcast::Sender<SystemEvent>,
+}
+
+impl EventBus {
+    /// 创建事件总线
+    pub fn new() -> Self {
+        let (tx, _) = broadcast::channel(1024);
+        Self { tx }
+    }
+
+    /// 发布事件
+    pub fn publish(&self, event: SystemEvent) {
+        let _ = self.tx.send(event);
+    }
+
+    /// 订阅事件
+    pub fn subscribe(&self) -> broadcast::Receiver<SystemEvent> {
+        self.tx.subscribe()
+    }
+}
+```
+
+### 3.2 SystemEvent
+
+```rust
+#[derive(Clone, Debug, Serialize)]
+pub enum SystemEvent {
+    // 视频事件
+    StreamStateChanged {
+        state: String,
+        device: Option<String>,
+        resolution: Option<Resolution>,
+        fps: Option<f32>,
+    },
+
+    VideoDeviceChanged {
+        added: Vec<String>,
+        removed: Vec<String>,
+    },
+
+    // HID 事件
+    HidStateChanged {
+        backend: String,
+        initialized: bool,
+        keyboard_connected: bool,
+        mouse_connected: bool,
+        mouse_mode: String,
+        error: Option<String>,
+    },
+
+    // MSD 事件
+    MsdStateChanged {
+        mode: String,
+        connected: bool,
+        image: Option<String>,
+        error: Option<String>,
+    },
+
+    MsdDownloadProgress {
+        download_id: String,
+        downloaded: u64,
+        total: u64,
+        speed: u64,
+    },
+
+    // ATX 事件
+    AtxStateChanged {
+        power_on: bool,
+        last_action: Option<String>,
+        error: Option<String>,
+    },
+
+    // 音频事件
+    AudioStateChanged {
+        enabled: bool,
+        streaming: bool,
+        device: Option<String>,
+        error: Option<String>,
+    },
+
+    // 配置事件
+    ConfigChanged {
+        section: String,
+    },
+
+    // 设备信息汇总
+    DeviceInfo {
+        video: VideoInfo,
+        hid: HidInfo,
+        msd: MsdInfo,
+        atx: AtxInfo,
+        audio: AudioInfo,
+    },
+
+    // 系统错误
+    SystemError {
+        module: String,
+        severity: String,
+        message: String,
+    },
+
+    // RustDesk 事件
+    RustDeskStatusChanged {
+        status: String,
+        device_id: Option<String>,
+        error: Option<String>,
+    },
+
+    RustDeskConnectionOpened {
+        connection_id: String,
+        peer_id: String,
+    },
+
+    RustDeskConnectionClosed {
+        connection_id: String,
+        peer_id: String,
+        reason: String,
+    },
+}
+```
+
+---
+
+## 4. 设备信息广播器
+
+在 `main.rs` 中启动的后台任务：
+
+```rust
+pub fn spawn_device_info_broadcaster(
+    state: Arc<AppState>,
+    events: Arc<EventBus>,
+) -> JoinHandle<()> {
+    tokio::spawn(async move {
+        let mut rx = events.subscribe();
+        let mut debounce = tokio::time::interval(Duration::from_millis(100));
+        let mut pending = false;
+
+        loop {
+            tokio::select! {
+                // 收到事件
+                result = rx.recv() => {
+                    if result.is_ok() {
+                        pending = true;
+                    }
+                }
+
+                // 防抖定时器
+                _ = debounce.tick() => {
+                    if pending {
+                        pending = false;
+                        // 收集设备信息
+                        let device_info = state.get_device_info().await;
+                        // 广播
+                        events.publish(SystemEvent::DeviceInfo(device_info));
+                    }
+                }
+            }
+        }
+    })
+}
+```
+
+---
+
+## 5. WebSocket 事件推送
+
+```rust
+pub async fn ws_handler(
+    ws: WebSocketUpgrade,
+    State(state): State<Arc<AppState>>,
+) -> impl IntoResponse {
+    ws.on_upgrade(|socket| handle_ws(socket, state))
+}
+
+async fn handle_ws(mut socket: WebSocket, state: Arc<AppState>) {
+    let mut rx = state.events.subscribe();
+
+    loop {
+        tokio::select! {
+            // 发送事件给客户端
+            result = rx.recv() => {
+                if let Ok(event) = result {
+                    let json = serde_json::to_string(&event).unwrap();
+                    if socket.send(Message::Text(json)).await.is_err() {
+                        break;
+                    }
+                }
+            }
+
+            // 接收客户端消息
+            msg = socket.recv() => {
+                match msg {
+                    Some(Ok(Message::Close(_))) | None => break,
+                    _ => {}
+                }
+            }
+        }
+    }
+}
+```
+
+---
+
+## 6. 使用示例
+
+### 6.1 发布事件
+
+```rust
+// 视频模块发布状态变更
+events.publish(SystemEvent::StreamStateChanged {
+    state: "streaming".to_string(),
+    device: Some("/dev/video0".to_string()),
+    resolution: Some(Resolution { width: 1920, height: 1080 }),
+    fps: Some(30.0),
+});
+
+// HID 模块发布状态变更
+events.publish(SystemEvent::HidStateChanged {
+    backend: "otg".to_string(),
+    initialized: true,
+    keyboard_connected: true,
+    mouse_connected: true,
+    mouse_mode: "absolute".to_string(),
+    error: None,
+});
+```
+
+### 6.2 订阅事件
+
+```rust
+let mut rx = events.subscribe();
+
+loop {
+    match rx.recv().await {
+        Ok(SystemEvent::StreamStateChanged { state, .. }) => {
+            println!("Stream state: {}", state);
+        }
+        Ok(SystemEvent::HidStateChanged { backend, .. }) => {
+            println!("HID backend: {}", backend);
+        }
+        Err(_) => break,
+    }
+}
+```
+
+---
+
+## 7. 前端事件处理
+
+```typescript
+// 连接 WebSocket
+const ws = new WebSocket('/api/ws');
+
+ws.onmessage = (event) => {
+    const data = JSON.parse(event.data);
+
+    switch (data.type) {
+        case 'StreamStateChanged':
+            updateStreamStatus(data);
+            break;
+        case 'HidStateChanged':
+            updateHidStatus(data);
+            break;
+        case 'MsdStateChanged':
+            updateMsdStatus(data);
+            break;
+        case 'DeviceInfo':
+            updateAllDevices(data);
+            break;
+    }
+};
+```
+
+---
+
+## 8. 最佳实践
+
+### 8.1 事件粒度
+
+- 使用细粒度事件便于精确更新
+- DeviceInfo 用于初始化和定期同步
+
+### 8.2 防抖
+
+- 使用 100ms 防抖避免事件风暴
+- 合并多个快速变更
+
+### 8.3 错误处理
+
+- 发布失败静默忽略 (fire-and-forget)
+- 订阅者断开自动清理