Daily update on 20250414-003153 by Nitload Youmu. Additional Message : Tech Issue: due to forbidden of multi-inheritance in C#, full ranslate fron EXPRESS to C# code is impossible, the EXPRESS interpreter in StgSharp will become a dialect

Add: A group of classes imported from lib https://github.com/ixmilia/step under MIT license, representing all STEP AP203 geometry objects
Change: many change to classes from https://github.com/ixmilia/step to link data interfaces to those in StgSharp
Freeze: implementation to StgSharp EXPRESS interpreter about collextion operation and element define grammer

Signed-off-by: Nitload <YoumuLiu_NSI@whv0t.onmicrosoft.com>

StgSharp.Script/Express/ExpElmentSource.cs

@@ -45,6 +45,8 @@ namespace StgSharp.Script.Express
 
         string Name { get; }
 
+        public void AddMember( string name, ExpNode memberNode );
+
         public void Analyse();
 
         public bool TryGetMember( string name, out ExpNode memberNode );