Replace per-triple provenance reification with subgraph model
Extraction provenance previously created a full reification (statement
URI, activity, agent) for every single extracted triple, producing ~13
provenance triples per knowledge triple. Since each chunk is processed
by a single LLM call, this was both redundant and semantically
inaccurate.
Now one subgraph object is created per chunk extraction, with
tg:contains linking to each extracted triple. For 20 extractions from
a chunk this reduces provenance from ~260 triples to ~33.
- Rename tg:reifies -> tg:contains, stmt_uri -> subgraph_uri
- Replace triple_provenance_triples() with subgraph_provenance_triples()
- Refactor kg-extract-definitions and kg-extract-relationships to
generate provenance once per chunk instead of per triple
- Add subgraph provenance to kg-extract-ontology and kg-extract-agent
(previously had none)
- Update CLI tools and tech specs to match
Also rename tg-show-document-hierarchy to tg-show-extraction-provenance.
Added extra typing for extraction provenance, fixed extraction prov CLI
