graft_query() is the advanced read-only retrieval surface. It accepts a
named request rather than SQL. Supported operations are "lookup",
"identifiers", "claims", "evidence", "neighbors", "traverse",
"unresolved", and "integrity".
Details
Request members are operation-specific: exact identifier lookup accepts
namespace, value, and optional class; identifiers and claims accept
id; evidence accepts statement_id or source_id; graph operations
accept their bounded path and projection arguments; unresolved mentions
accept optional class and source_id; and integrity accepts projections.
Unknown members are rejected. Tabular results carry limit, truncated,
and store_schema_digest attributes.
A GraftView pins every operation and does not support "integrity".