[coop §4 harness] session=C3
[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=   1.07ms V1=  38.46ms SDPA=   2.56ms V1/V2=35.90× SDPA/V2= 2.39× drift=32.7%
  lcsa_small_seq4k_sparse          d=0.067 V2=   0.97ms V1=  11.11ms SDPA=   2.57ms V1/V2=11.44× SDPA/V2= 2.65× drift=57.8%
  lcsa_mid_seq8k                   d=0.119 V2=   1.42ms V1=  51.20ms SDPA=   6.45ms V1/V2=36.17× SDPA/V2= 4.55× drift=33.2%
  lcsa_mid_seq8k_sparse            d=0.030 V2=   1.16ms V1=  13.19ms SDPA=   6.47ms V1/V2=11.40× SDPA/V2= 5.59× drift=65.0%
  lcsa_large_seq16k                d=0.120 V2=   2.04ms V1= 103.97ms SDPA=  12.74ms V1/V2=50.99× SDPA/V2= 6.25× drift= 3.1%
  lcsa_large_seq16k_sparse         d=0.030 V2=   1.03ms V1=  27.55ms SDPA=  12.83ms V1/V2=26.87× SDPA/V2=12.51× drift=26.2%
  lcsa_mid_seq8k_very_sparse       d=0.011 V2=   0.63ms V1=   5.37ms SDPA=   6.46ms V1/V2= 8.54× SDPA/V2=10.29× drift=24.2%

[coop §4 harness] density sweep on lcsa_mid_seq8k
  d=0.01 d_act=0.011 V2=   0.79ms V1=   5.56ms SDPA=   6.48ms V1/V2= 7.04× SDPA/V2= 8.21×
  d=0.03 d_act=0.030 V2=   0.78ms V1=  13.87ms SDPA=   6.65ms V1/V2=17.85× SDPA/V2= 8.56×
  d=0.05 d_act=0.049 V2=   0.84ms V1=  21.64ms SDPA=   6.46ms V1/V2=25.67× SDPA/V2= 7.66×
  d=0.10 d_act=0.102 V2=   1.18ms V1=  43.64ms SDPA=   6.45ms V1/V2=37.13× SDPA/V2= 5.49×
  d=0.20 d_act=0.199 V2=   1.67ms V1=  85.48ms SDPA=   6.45ms V1/V2=51.14× SDPA/V2= 3.86×
  d=0.50 d_act=0.500 V2=   3.32ms V1= 210.30ms SDPA=   6.51ms V1/V2=63.38× SDPA/V2= 1.96×

[coop §4 harness] session 'C3' → docs/lcsa-nax/lcsa-nax-coop-rewrite-data.json
