[coop §4 harness] session=C1
[coop §4 harness] correctness smoke (V1 vs V2)...
  smoke: rmse=1.2821e-06 maxerr=7.6294e-06 NaN=0 Inf=0 -> PASS
[coop §4 harness] initial cooldown 180.0s

[coop §4 harness] production shapes A/B/A V2→V1→V2
  lcsa_small_seq4k                 d=0.239 V2=   1.14ms V1=  38.73ms SDPA=   2.56ms V1/V2=33.93× SDPA/V2= 2.24× drift=37.4%
  lcsa_small_seq4k_sparse          d=0.067 V2=   0.96ms V1=  11.29ms SDPA=   2.54ms V1/V2=11.73× SDPA/V2= 2.64× drift=61.6%
  lcsa_mid_seq8k                   d=0.119 V2=   1.52ms V1=  54.31ms SDPA=   6.61ms V1/V2=35.79× SDPA/V2= 4.35× drift=32.6%
  lcsa_mid_seq8k_sparse            d=0.030 V2=   1.10ms V1=  13.48ms SDPA=   6.45ms V1/V2=12.23× SDPA/V2= 5.85× drift=58.6%
  lcsa_large_seq16k                d=0.120 V2=   2.06ms V1= 103.91ms SDPA=  12.73ms V1/V2=50.46× SDPA/V2= 6.18× drift= 0.7%
  lcsa_large_seq16k_sparse         d=0.030 V2=   1.10ms V1=  27.15ms SDPA=  12.75ms V1/V2=24.63× SDPA/V2=11.57× drift=34.1%
  lcsa_mid_seq8k_very_sparse       d=0.011 V2=   0.91ms V1=   5.57ms SDPA=   6.45ms V1/V2= 6.11× SDPA/V2= 7.08× drift=60.8%

[coop §4 harness] density sweep on lcsa_mid_seq8k
  d=0.01 d_act=0.011 V2=   0.71ms V1=   5.13ms SDPA=   6.52ms V1/V2= 7.28× SDPA/V2= 9.24×
  d=0.03 d_act=0.030 V2=   1.27ms V1=  13.16ms SDPA=   6.44ms V1/V2=10.37× SDPA/V2= 5.08×
  d=0.05 d_act=0.049 V2=   0.97ms V1=  21.39ms SDPA=   6.46ms V1/V2=21.96× SDPA/V2= 6.63×
  d=0.10 d_act=0.102 V2=   1.17ms V1=  43.55ms SDPA=   6.43ms V1/V2=37.25× SDPA/V2= 5.50×
  d=0.20 d_act=0.199 V2=   2.23ms V1=  85.64ms SDPA=   6.45ms V1/V2=38.34× SDPA/V2= 2.89×
  d=0.50 d_act=0.500 V2=   3.32ms V1= 211.06ms SDPA=   6.45ms V1/V2=63.59× SDPA/V2= 1.94×

[coop §4 harness] session 'C1' → docs/lcsa-nax/lcsa-nax-coop-rewrite-data.json
