Find class_uri for PolymerSample that is different from SubstanceSample #103
Description
Affected: chem_dcat_ap.yaml
Severity: Minor - already tracked as TODO in schema
Status: Known issue
Problem: PolymerSample and SubstanceSample both map to class_uri: SIO:001378. Their RDF output is indistinguishable at the type level. A downstream consumer seeing ex:x a SIO:001378 cannot determine whether the instance is a polymer sample or a general substance sample without examining additional properties.
Action: Find a more specific ontology term for PolymerSample. Candidates: ChEBI polymer-related classes, or a new CHMO? term if nothing suitable exists elsewhere in OBO.