1# Verification checks (P4)21. Clean re-run reproduces results.json byte-identically (cmp) — PASS.32. n_analysed (400) = n_input_rows (400) − removed (0) — PASS.43. se_iid, se_hac > 0 — PASS (0.0448, 0.0654).54. CI [-0.0264, 0.2299] contains beta_hat 0.1017 and is symmetric: beta ± 1.96·se_hac — PASS.65. t_hac = beta_hat/se_hac = 1.556; p_hac = 2Φ(-|t|) = 0.120 — PASS.76. Baseline matches memo (alpha 2.0925, beta 0.1017, se 0.0448, t 2.27, p 0.0238) — PASS.87. Magnitude: se_hac/se_iid = 1.46 > 1, consistent with positive autocorrelation in residuals (rho 0.61) and persistent x — PASS.98. memo_claim_supported == (p_hac < 0.05) == false; CI includes 0 consistent with p > 0.05 — PASS.109. Sensitivity: p_hac in [0.097, 0.123] for all lags 5..36; only lag 0 (no autocorrelation correction) gives p<0.05 — conclusion robust — PASS.11