Provenance-tagged knowledge graph store.
Every edge in a Roteiro graph carries a [Provenance] tag recording how it
was produced: deterministically derived from source ASTs, authored by a
human or agent in an ADR/blueprint, or inferred heuristically from docs and
other artifacts. See ADR-0001.
The graph is a set of [Node]s addressed by a deterministic natural
[Node::key], connected by [Edge]s. Facts extracted from one source blob
are grouped into a [FactSet] and applied atomically to a [Store].
@rto:0001