Phase 1: dependency-free single-rank AMICA build (MPI shim + static LAPACK) #166

Part of epic #165. Extend sccn/amica PR #53's no-MKL recipe with a single-rank MPI shim and static LAPACK/BLAS so amica15 builds into a dependency-free binary that runs with no brew/apt install. Validate the built binary against the Fortran reference LL on real sample EEG.