Fix schemaorg-grammar subclass handling for priceSpecification range checks

[ziodave]

Summary

• fix false-positive Schema.org range check: priceSpecification. warnings when the value is a valid subclass (for example schema:UnitPriceSpecification)
• add a bundled schema.org subclass ontology (rdfs:subClassOf) used to resolve subclass relationships during issue extraction
• apply the same subclass-aware filtering in both validation issue extraction and graph-audit schema compliance extraction
• add regression tests for positive and negative priceSpecification range behavior and graph-audit coverage of the case

Why

Bluehost case artifacts reproduced a warning for:

• Offer -> priceSpecification -> UnitPriceSpecification

That should be treated as valid subclass usage.

Implementation Notes

• kept validator behavior scoped: no global ontology inference changes for all shapes
• instead, filter only schema.org grammar range-check warnings when the warning value type is a subclass of the expected class from the source shape

Tests

• uv run pytest tests/test_product_snippet_validation.py -k schemaorg_grammar_price_specification -q
• uv run pytest tests/test_graph_audit.py -k "unit_price_specification_no_range_warning or auditor_uses_schema_validation_for_rich_snippets" -q
• uv run python tests/tools/run_slice_tests.py graph -- -q
• uv run python tests/tools/run_slice_tests.py validation -- -q