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/Exception.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <sstream>
+#include <stdexcept>
+
+namespace Base {
+
+class Exception : public std::runtime_error
+{
+public:
+    using std::runtime_error::runtime_error;
+
+    void reportException() const {}
+};
+
+class RuntimeError : public Exception
+{
+public:
+    using Exception::Exception;
+};
+
+class ValueError : public Exception
+{
+public:
+    using Exception::Exception;
+};
+
+}  // namespace Base
+
+#define FC_THROWM(type, message) \
+    do { \
+        std::ostringstream freecad_naming_probe_exception_stream; \
+        freecad_naming_probe_exception_stream << message; \
+        throw type(freecad_naming_probe_exception_stream.str()); \
+    } while (false)