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/Writer.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <ostream>
+#include <sstream>
+
+namespace Base {
+
+class Writer
+{
+public:
+    std::ostream& Stream()
+    {
+        return stream;
+    }
+
+    const char* ind() const
+    {
+        return "";
+    }
+
+    const char* addFile(const char* name, const void*)
+    {
+        return name;
+    }
+
+    std::ostream& beginCharStream()
+    {
+        return stream;
+    }
+
+    std::ostream& endCharStream()
+    {
+        return stream;
+    }
+
+private:
+    std::ostringstream stream;
+};
+
+}  // namespace Base