follow stab55_35, 1. implement distributed Strict-MG runtime: fine face halo by default, coarse full/compact vector+link halos, R/P boundary contracts, global FGMRES reductions and multi-rank fused-coarse fallback; 2. fix dot_many device write-back, vector-halo component stride, compact link-halo packing and backward-correction sign found by the new MPI probes; 3. add distributed Galerkin setup (periodic face-exchange roll + halo-padded fine operator) with process_grid/comm plumbing and fail-closed gates; 4. align finest-level total iteration semantics with QUDA outer GCR/FGMRES total_iter and add strict trace v3 iteration_count records; 5. land collector phase/device/MPI extensions, full matrix orchestrator and JSON->CSV/SVG/PDF/LaTeX report generator with the V100 c64 matrix and documented MG-1/c128/P100 gaps; evidence: c128 coarse operators match the global reference to 1e-16 on 1/2/4 ranks and distributed solves reach <1e-6 true residual. [codex].