Enrich the `aura graph` / `aura sweep` sample blueprint into a "trend + momentum,
weighted blend" strategy that showcases four authoring/viewer capabilities the
single-level sample left dark: multiply-nested composites, a multi-param node
inside a composite, a multi-output (MACD-like) node, and bind() (a param fixed as
a structural constant, dropped from the sweep surface). Pure authoring over
already-shipped primitives — no engine semantics or viewer change; reuses the
existing sma_cross/macd builders.
Auto-signed under /boss (spec auto-sign enabled): objective gates green
(precondition clean, self-review clean, grounding-check PASS) and a unanimous
five-lens spec-skeptic panel (criterion, grounding, scope-fork, ambiguity,
plan-readiness) returned SOUND. Design provenance recorded on #62.
refs #62
Brummel
e7393f6809