在 AiVideo 中能看到图像

增加了在线状态同步逻辑

SHH.Contracts/Commands/DeviceStatusEvent.cs

@@ -0,0 +1,49 @@
+using MessagePack;
+using System.Collections.Generic;
+
+namespace SHH.Contracts
+{
+    /// <summary>
+    /// [控制面] 状态全量快照包
+    /// </summary>
+    [MessagePackObject]
+    public class StatusBatchPayload
+    {
+        // [新增] 协议类型标识 (人工可读)
+        // 建议值: "STATUS_BATCH" 或 "设备状态全量包"
+        [Key(0)]
+        public string Protocol { get; set; } = "STATUS_BATCH";
+
+        [Key(1)]
+        public List<StatusEventPayload> Items { get; set; }
+            = new List<StatusEventPayload>();
+
+        [Key(2)]
+        public long Timestamp { get; set; }
+    }
+
+    /// <summary>
+    /// [控制面] 设备状态变更通知包
+    /// </summary>
+    [MessagePackObject]
+    public class StatusEventPayload
+    {
+        [Key(0)]
+        public string CameraId { get; set; }
+
+        /// <summary>
+        /// true: 上线/活跃, false: 离线/超时
+        /// </summary>
+        [Key(1)]
+        public bool IsOnline { get; set; }
+
+        /// <summary>
+        /// 变更原因 (e.g. "Ping Success", "Frame Timeout")
+        /// </summary>
+        [Key(2)]
+        public string Reason { get; set; }
+
+        [Key(3)]
+        public long Timestamp { get; set; }
+    }
+}