Brummel
bbe2266b9e
Iteration 1 of the graph render redesign: a read-only model_to_json(&Composite) in a new crates/aura-engine/src/graph_model.rs, hand-rolled deterministic JSON (RunReport::to_json house style, no serde). Six tasks: helpers, primitive record, scope (index keys + synthetic source nodes from bound roles), composite defs (@role/#N endpoints, distinct-once walk), top-level + byte golden + determinism, structural assertions + structural-miswire-differs + read-only. Decisions: home in aura-engine; node keys are indices (C23); input ports carry kind+firing, no name (per acceptance criterion 3); bound root source-roles minted as synthetic source nodes.