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.

config/freecad-wasm-sdk-compat.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#ifdef __EMSCRIPTEN__
+#if __has_include(<Standard_Macro.hxx>)
+#include <TopTools_HSequenceOfShape.hxx>
+#include <TopTools_ListOfShape.hxx>
+#endif
+
+// QTimeZone::UTC remains available when Qt's WASM timezone backend is off.
+#define systemTimeZone() UTC
+#endif