follow stab55_10, 1. vectorize strict colored Galerkin support gather/scatter and cache target groups; 2. add explicit c128 CPU block staging and null-basis offload options; 3. verify c128 setup 44.86 s -> 16.67 s with true residual 1.84e-8 unchanged; 4. add CUDA regression, protocol tests, report and skill notes. [opencode].