[coop §4 harness] session=C2
[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=   1.16ms V1=  38.62ms SDPA=   2.58ms V1/V2=33.31× SDPA/V2= 2.22× drift=36.3%
  lcsa_small_seq4k_sparse          d=0.067 V2=   1.03ms V1=  11.35ms SDPA=   2.58ms V1/V2=11.02× SDPA/V2= 2.51× drift=61.1%
  lcsa_mid_seq8k                   d=0.119 V2=   1.60ms V1=  51.52ms SDPA=   6.45ms V1/V2=32.15× SDPA/V2= 4.03× drift=36.1%
  lcsa_mid_seq8k_sparse            d=0.030 V2=   0.85ms V1=  13.57ms SDPA=   6.46ms V1/V2=16.03× SDPA/V2= 7.64× drift=33.6%
  lcsa_large_seq16k                d=0.120 V2=   2.55ms V1= 103.23ms SDPA=  12.72ms V1/V2=40.53× SDPA/V2= 4.99× drift=39.5%
  lcsa_large_seq16k_sparse         d=0.030 V2=   1.24ms V1=  27.00ms SDPA=  12.85ms V1/V2=21.78× SDPA/V2=10.36× drift=38.7%
  lcsa_mid_seq8k_very_sparse       d=0.011 V2=   0.62ms V1=   5.42ms SDPA=   6.44ms V1/V2= 8.78× SDPA/V2=10.44× drift=37.9%

[coop §4 harness] density sweep on lcsa_mid_seq8k
  d=0.01 d_act=0.011 V2=   0.70ms V1=   5.15ms SDPA=   6.49ms V1/V2= 7.35× SDPA/V2= 9.26×
  d=0.03 d_act=0.030 V2=   0.82ms V1=  13.19ms SDPA=   6.48ms V1/V2=16.01× SDPA/V2= 7.86×
  d=0.05 d_act=0.049 V2=   0.85ms V1=  21.32ms SDPA=   6.44ms V1/V2=24.95× SDPA/V2= 7.54×
  d=0.10 d_act=0.102 V2=   1.22ms V1=  43.64ms SDPA=   6.45ms V1/V2=35.89× SDPA/V2= 5.30×
  d=0.20 d_act=0.199 V2=   1.72ms V1=  84.92ms SDPA=   6.44ms V1/V2=49.27× SDPA/V2= 3.74×
  d=0.50 d_act=0.500 V2=   3.31ms V1= 211.99ms SDPA=   6.43ms V1/V2=64.10× SDPA/V2= 1.95×

[coop §4 harness] session 'C2' → docs/lcsa-nax/lcsa-nax-coop-rewrite-data.json
