Brummel
4f72701e3b
The second walking-skeleton cycle, on top of the 0001 streaming substrate: the Node contract (C8) and its evaluation context. Scope (one iteration): - `Node` trait — `schema() -> NodeSchema` (inputs: kind + lookback; output kind) + `eval(&mut self, Ctx) -> Option<Scalar>` (None = filter / not warmed). - `Ctx` — a Copy borrow-wrapper handing eval zero-copy, financial-indexed Windows per input (`ctx.f64_in(i)[k]`, index 0 = newest). - Read-side `AnyColumn::as_f64/as_i64/as_bool/as_ts` — mirrors the existing write-side `as_*_mut` and closes the cycle-0001 audit gap. - `Sma` in aura-std — the worked producer node (the skeleton's first block), driven by a hand-written test that mimics the future sim loop. Deliberate deferrals (recorded as decisions, not gaps): the sim loop (C4), freshness gating (C5), firing policies (C6, so InputSpec carries no firing field yet), schema-level tunable params (C12/C19), and sinks / no-output nodes (C8 consumer side). The hand-driven test stands in for the loop. Grounding-check PASS: all load-bearing assumptions about the 0001 substrate (Column/Window/AnyColumn/Scalar, financial indexing) ratified by green tests. refs walking-skeleton