feat: add candidate FreeCAD naming SDK and attachment oracles

Build and verify the candidate-only FreeCAD naming bridge and OCCT worker path, including three-stage StringHasher restoration. Add Datum, ShapeBinder, attachment-mode, and PartDesign structure oracles plus offline SDK build plans and CI boundary checks.

native/freecad-naming-probe/shims/Base/Persistence.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <CXX/Objects.hxx>
+
+namespace Base {
+
+class Reader;
+class Writer;
+class XMLReader;
+
+class BaseClass
+{
+public:
+    virtual ~BaseClass() = default;
+    virtual PyObject* getPyObject()
+    {
+        return nullptr;
+    }
+};
+
+class Persistence : public BaseClass
+{
+public:
+    ~Persistence() override = default;
+
+    virtual unsigned int getMemSize() const = 0;
+    virtual void Save(Writer&) const = 0;
+    virtual void Restore(XMLReader&) = 0;
+    virtual void SaveDocFile(Writer&) const = 0;
+    virtual void RestoreDocFile(Reader&) = 0;
+};
+
+}  // namespace Base
+
+#define TYPESYSTEM_HEADER()
+#define TYPESYSTEM_HEADER_WITH_OVERRIDE()
+#define TYPESYSTEM_SOURCE(...)
+#define TYPESYSTEM_SOURCE_ABSTRACT(...)