fix 任务生成优化

Src/Dlhis.Basic/Summary/Response/AttendanceDeviceSummary.cs

@@ -12,13 +12,18 @@ public class AttendanceDeviceSummary
     /// <summary>
     /// 在线数
     /// </summary>
-    public int OnlineCount  { get; set; }
+    public int OnlineCount { get; set; }
 
     /// <summary>
     /// 启用数
     /// </summary>
     public int EnableCount { get; set; }
 
+    /// <summary>
+    /// 离线数
+    /// </summary>
+    public int OfflineCount => Total - OnlineCount;
+
     /// <summary>
     /// 新增设备趋势 30天内
     /// </summary>

Src/Dlhis.Basic/Summary/Services/Implements/SummaryService.cs

@@ -53,7 +53,7 @@ public class SummaryService : ISummaryService
                 {
                     if (x.HeartbeatInterval <= 0)
                     {
-                        return false;
+                        return true;
                     }
 
                     return x.LastHeartbeatTime.AddSeconds(x.HeartbeatInterval * 3) >= now;