- New script: protocol/examples/penalty_lam_3seed_summary.py
  Loads existing penalty JSON files for lam=1e-3 and lam=1e-2 across
  seeds, computes 3-seed mean margin vs DFA-shallow baseline, and
  explicitly checks the (d) verdict at 2pp threshold per seed and
  in aggregate. Reports MIXED if seeds disagree.

  Current result: lam=1e-2 has 3 seeds (margin +1.38 ± 0.05 pp, all
  FIRE), lam=1e-3 has 1 seed (+2.31 pp, PASSES). Awaiting s123/s456
  for lam=1e-3.

- experiments/dfa_residual_penalty_test.py: now saves model checkpoint
  + Bs alongside JSON log so post-hoc protocol can be applied without
  re-running. Closes the pitfall #6.5 self-disclosure (auxiliary nets
  must be saved for post-hoc Gamma to be reconstructible).