Dry run, 2026-10-13 08:25 Halifax: old start 1 (seed 0), 600 units, fresh copies made at t = 200 and 250
  in one go: 37.7 s; in pieces: stopped 13 times and gone on from the kept state
  reproduces the saved run exactly: {'coherence': True, 'gap': True, 'settling': True}
  pieces agree with one go to the last digit: {'z': True, 'logs': True, 'trace': True, 'fresh_logs': True, 'overlap': True}
  twin (a fresh copy that is the carried copy): largest log difference 0, largest |overlap - 1| 3.33e-16
  the other three fresh gaps: every number present True; G = [0.0049, 0.0055, 0.0071] against W = 0.0028 (t = 200 copy) and 0.0024 (t = 250 copy)
  overlap of the t = 250 copies at 5, 25, 100, 300 units: [0.041, 0.055, 0.076, 0.098]; [0.009, 0.086, 0.318, 0.255]
  the cause test's locked files unchanged: True
  dry run passed