Extends the existing ontology and triplet-store stack with first-class
SKOS support without adding any new top-level packages.
### semantica/ontology/namespace_manager.py
- `get_skos_uri(local_name)` — build full skos:core# URI from local name
- `build_concept_scheme_uri(name)` — slug a human name into a stable
ConceptScheme URI anchored at the configured base URI
### semantica/triplet_store/triplet_store.py
- `add_skos_concept(concept_uri, scheme_uri, pref_label, ...)` — asserts
ConceptScheme + Concept triples, prefLabel, altLabel, broader, narrower,
related, definition, notation via existing `add_triplets()` API
- `get_skos_concepts(scheme_uri=None)` — SPARQL SELECT via `execute_query()`,
collapses multi-valued bindings into concept dicts
### semantica/ontology/engine.py
- `list_vocabularies()` — list all skos:ConceptScheme instances
- `list_concepts(scheme_uri)` — list concepts in a scheme with alt labels
- `search_concepts(query, scheme_uri=None)` — case-insensitive substring
search over prefLabel + altLabel; sanitises user input against SPARQL injection
### tests
- `TestSKOSOntologyEngine` (14 tests) in test_ontology_comprehensive.py
- `TestSKOSTripletStore` (6 tests) in test_triplet_store.py
- All 1162 existing + new tests pass, 0 failures
### docs/reference/ontology.md
- New "SKOS Vocabulary Management" section: data-model table, import
examples (add_skos_concept + rdflib bulk), list/search API, NamespaceManager helpers
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
