Add attributes needed for resource synchronization

src/Moryx.AbstractionLayer/Resources/Attributes/ResourceSynchronizationAttribute.cs

@@ -0,0 +1,36 @@
+// Copyright (c) 2025, Phoenix Contact GmbH & Co. KG
+// Licensed under the Apache License, Version 2.0
+
+using System;
+
+namespace Moryx.AbstractionLayer.Resources.Attributes;
+
+/// <summary>
+/// Specifies the synchronization behavior for a resource's digital twin
+/// across multiple application instances.
+/// </summary>
+[AttributeUsage(AttributeTargets.Class, Inherited = false)]
+public class ResourceSynchronizationAttribute: Attribute
+{
+    /// <summary>
+    /// Defines the property serialization strategy for this resource.
+    /// </summary>
+    public SynchronizationMode Mode { get; set; }
+}
+
+/// <summary>
+/// Defines the property serialization strategy.
+/// </summary>
+public enum SynchronizationMode
+{
+    /// <summary>
+    /// The entire resource object, including all its properties, is serialized and synchronized.
+    /// </summary>
+    Full,
+
+    /// <summary>
+    /// Only properties explicitly marked with the [SynchronizableMember] attribute will be 
+    /// serialized and synchronized.
+    /// </summary>
+    Selective
+}

src/Moryx.AbstractionLayer/Resources/Attributes/SynchronizableMemberAttribute.cs

@@ -0,0 +1,13 @@
+// Copyright (c) 2025, Phoenix Contact GmbH & Co. KG
+// Licensed under the Apache License, Version 2.0
+
+using System;
+
+namespace Moryx.AbstractionLayer.Resources.Attributes;
+
+/// <summary>
+/// Marks a property as included in the payload when its class
+/// is using 'Selective' synchronization mode.
+/// </summary>
+[AttributeUsage(AttributeTargets.Property)]
+public class SynchronizableMemberAttribute : Attribute { }

src/Moryx.AbstractionLayer/Resources/IResourceManagementChanges.cs

@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) 2025, Phoenix Contact GmbH & Co. KG
+// Licensed under the Apache License, Version 2.0
+
+using System;
 
 namespace Moryx.AbstractionLayer.Resources;