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/StringHasherPy.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <CXX/Objects.hxx>
+
+namespace App {
+
+class StringHasher;
+
+class StringHasherPy : public _object
+{
+public:
+    explicit StringHasherPy(StringHasher*) {}
+};
+
+}  // namespace App