Brummel
0998f9aabf
Applies the principle the user named: a node is a primitive only if it is NOT DAG-expressible from other primitives; a function that needs a missing primitive gets the primitive added, not fused away. - Remove the fused VolStop node (it was pure feed-forward arithmetic). - The volatility stop is now a composition of primitives, vol_stop(length, k): k * Sqrt(Ema(Mul(d,d), length)), d = Sub(price, Delay(price,1)) -- a rolling EWMA standard deviation. Built with GraphBuilder; proven end-to-end (bootstraps + runs + emits k*sigma) in tests/vol_stop_composite.rs. - Migrate the one VolStop caller (stage1_r_e2e.rs) off it: the R-is-stop-defined test now contrasts a tight vs a wide FixedStop (two constant distances still fold to different R, the property under test). Uses the Mul + Sqrt primitives added in the prior commit. FixedStop stays the only stop-rule primitive (a triggered constant). Full suite + clippy green. refs #117 #119