Literal objects (e.g. rdfs:label values) were not being inserted into the
quads_by_entity table with role='O', so queries like `tg-query-graph -o
MIL-HDBK-516D` returned no results even though the triple existed.
Removed the otype guard that skipped entity row insertion for literals in
both insert() and async_insert(). Also updated delete_collection() and
async_delete_collection() to include literal objects in entity partition
cleanup.
Existing data requires re-ingestion for old literal objects to become
queryable by object value.
Schema fix (dtype/lang clustering key):
- Add dtype and lang to PRIMARY KEY in quads_by_entity table
- Add otype, dtype, lang to PRIMARY KEY in quads_by_collection table
- Fixes deduplication bug where literals with same value but different
datatype or language tag were collapsed (e.g., "thing" vs "thing"@en)
- Update delete_collection to pass new clustering columns
- Update tech spec to reflect new schema
Graph filter semantics (simplified, no wildcard constant):
- g=None means all graphs (no filter)
- g="" means default graph only
- g="uri" means specific named graph
- Remove GRAPH_WILDCARD usage from EntityCentricKnowledgeGraph
- Fix service.py streaming and non-streaming paths
- Fix CLI to preserve empty string for -g '' argument
