Re-organize all projects (#4166)

Content.Shared/Construction/Steps/NestedConstructionGraphStep.cs

@@ -0,0 +1,28 @@
+#nullable enable
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Utility;
+
+namespace Content.Shared.Construction.Steps
+{
+    [DataDefinition]
+    public class NestedConstructionGraphStep : ConstructionGraphStep, ISerializationHooks
+    {
+        [DataField("steps")] public List<List<ConstructionGraphStep>> Steps { get; private set; } = new();
+
+        void ISerializationHooks.AfterDeserialization()
+        {
+            if (Steps.Any(inner => inner.Any(step => step is NestedConstructionGraphStep)))
+            {
+                throw new InvalidDataException("Can't have nested construction steps inside nested construction steps!");
+            }
+        }
+
+        public override void DoExamine(FormattedMessage message, bool inDetailsRange)
+        {
+        }
+    }
+}