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/StringIDPy.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <CXX/Objects.hxx>
+
+namespace App {
+
+class StringID;
+
+class StringIDPy : public _object
+{
+public:
+    explicit StringIDPy(StringID*) {}
+
+    int _index = 0;
+};
+
+}  // namespace App