Flag-Enum implementiert und IServiceMessage mit Flag-Unterstützung aktualisiert

- Flag-Enum mit Null und SecurityBreach definiert.
- Flag-Eigenschaft und HasFlag-Methode zu IServiceMessage hinzugefügt.

DigitalData.Core.Application/Flag.cs

@@ -0,0 +1,19 @@
+namespace DigitalData.Core.Application
+{
+    /// <summary>
+    /// Defines flags that indicate specific types of status or conditions in a service operation.
+    /// These flags help in categorizing and identifying specific circumstances or issues that may arise during execution.
+    /// </summary>
+    public enum Flag
+    {
+        /// <summary>
+        /// Indicates that no specific condition or status is associated with the service operation.
+        /// </summary>
+        Null,
+
+        /// <summary>
+        /// Indicates a security breach or vulnerability has been detected during the service operation.
+        /// </summary>
+        SecurityBreach
+    }
+}