Grid-search winners on 100 noise histories (true Sharpe = 0)

Mean in-sample Sharpe:      0.98
Mean out-of-sample Sharpe:  0.08
Winners with PSR > 0.95:    42%  (fooled by luck)
Winners with DSR > 0.95:    0%

Control: one pre-registered idea on data with a real edge (N = 1, so DSR = PSR)

seed  1: in-sample Sharpe 1.13, DSR 0.975, hidden-year Sharpe 1.14
seed  2: in-sample Sharpe 1.58, DSR 0.997, hidden-year Sharpe 1.12
seed 42: in-sample Sharpe 2.64, DSR 1.000, hidden-year Sharpe 2.09
