Function complex_dot 

pub fn complex_dot(a: &[ComplexF64], b: &[ComplexF64]) -> ComplexF64

Complex dot product using BinnedAccumulator for deterministic results.

dot(a, b) = Σ a[i] * conj(b[i]) (standard Hermitian inner product).

Real and imaginary parts are accumulated separately via BinnedAccumulator.