1- 2026-10-30 P0 passed: contract written.2- 2026-10-30 P1 passed: audit found the file ends 2019-12-31 with n_treated=0. Decision: premise_invalid, no proxy.3- 2026-10-30 P2 passed: baseline mean change over the whole file = -0.0429 bp.4- 2026-10-30 P3 passed: analysis.py written; general Welch implementation, nulls when there are no treated rows.5- 2026-10-30 P4 passed: deterministic re-run identical; consistency checks recorded.6- 2026-10-30 P5 passed: report and claims written.7