sim rebalance from raw upstream: sim_starstruck → 166K (150K train + 16K test, stride=3); sim_tactile_mnist → 151K (102K train + 49K test, stride=2); refreshed sample grids

v7: I_min=12 (real) + I_min=10 (sim) reprocess of RTM and sims; add pixel_value_distribution chart; fix sim_tactile_mnist test routing; refresh all sample grids and composition charts.

Re-process sim_starstruck with unified A=40, I=10 rule

Add sim_starstruck (200K Mini-Taxim sim star touches)