Constant DEFAULT_DECOMP_X_MIN

pub const DEFAULT_DECOMP_X_MIN: f64 = 0.5;

Default frequency band for Gram-Schmidt and B&F decompositions.

PIXIE-like window in dimensionless frequency at T₀ = 2.725 K: x ∈ [0.5, 18] corresponds to ν ∈ [28, 1020] GHz. Matches the experimental band used in CJ2014 Appendix A.