- 2026-10-30 P0 contract written. - 2026-10-30 P1 audit: clean balanced data, no exclusions. - 2026-10-30 P2 baseline se_iid computed (naïve). - 2026-10-30 P3 decision: main SE = CR1 cluster-robust by school with t(G-1=39) reference; robustness = school-means regression. No randomness, seed null. - 2026-10-30 P4 verification and gate. - 2026-10-30 P4/P5 passed; gate receipts 20261030T043629.457750Z.json recorded. Task complete.