=== BP+pen 30ep s=123 ===
BP + ‖f‖² penalty: seed=123, lam=0.01, epochs=30
  ep 1: test_acc=0.3593
  ep 5: test_acc=0.4104
  ep 10: test_acc=0.4630
  ep 15: test_acc=0.4839
  ep 20: test_acc=0.5025
  ep 25: test_acc=0.5194
  ep 30: test_acc=0.5262

FINAL test acc: 0.5262
Compare to:
  BP-trainable (3-seed mean):   0.609
  Penalized DFA lam=1e-2:       0.363
  DFA-shallow:                  0.349

Margin vs DFA-shallow baseline: +17.72 pp
  → BP+penalty intermediate; partial capacity loss + residual mode 2
Saved results/bp_with_penalty/bp_pen_lam0.01_s123.json
=== BP+pen 30ep s=456 ===
BP + ‖f‖² penalty: seed=456, lam=0.01, epochs=30
  ep 1: test_acc=0.3652
  ep 5: test_acc=0.4027
  ep 10: test_acc=0.4639
  ep 15: test_acc=0.4963
  ep 20: test_acc=0.5189
  ep 25: test_acc=0.5345
  ep 30: test_acc=0.5397

FINAL test acc: 0.5397
Compare to:
  BP-trainable (3-seed mean):   0.609
  Penalized DFA lam=1e-2:       0.363
  DFA-shallow:                  0.349

Margin vs DFA-shallow baseline: +19.07 pp
  → BP+penalty intermediate; partial capacity loss + residual mode 2
Saved results/bp_with_penalty/bp_pen_lam0.01_s456.json
=== ALL DONE ===