Brummel
78d68fa8ad
Consolidate the node data structure so every node's signature (NodeSchema: inputs/output/params) exists in the blueprint pre-build, declared once. - Signature vs sizing split: NodeSchema becomes the static signature (InputSpec -> PortSpec, lookback removed); the one param-dependent quantity (input buffer lookback) moves to a build-time Node::lookbacks() query. Node::schema() is removed. - PrimitiveBuilder (ex-LeafFactory) carries the schema; the built node no longer re-declares it -> closes the params-declared-twice drift. - Blueprint collapses into Composite: Role gains source: Option<ScalarKind>; the root is the fully-bound composite (no "main graph"); new error UnboundRootRole. - compile -> FlatGraph -> bootstrap: FlatGraph carries node + signature in parallel; bootstrap sizes from lookbacks(), kind-checks from the signatures. - Renames: BlueprintNode::Leaf -> Primitive, LeafFactory -> PrimitiveBuilder. Behaviour-preserving (C1). Render is out of scope beyond compiling (next cycle). refs #43 #36