Borrowed IFC2X3/IFC4 classification, document, library and association semantics.
Views borrow [ifc_model::Model] and read every record against the
release its header declares (see [classification_schema]): slot
positions, selects and domains come from that release's bundled table.
Authoring helpers stage IFC4 records on a caller-owned
[ifc_model::Transaction]. No query performs external I/O.