Release 0.8.2

SOLVAX 0.8.2 adds galerkin_deflation, a balanced symmetry-preserving Galerkin coarse correction \(S+(I-SA)PA_c^{-1}P^T(I-AS)\) for fixed SPD preconditioners used with PCG. Given a symmetric smoother, a prolongation, and the Galerkin coarse operator \(A_c=P^TAP\), the two-level inverse stays symmetric positive definite, so it is safe inside the strict PCG preconditioner contract. See the Galerkin-deflation section of Preconditioners.