Reproducibility snapshot v1.0.0 for "Compound-hazard cascade on grid-served municipal distributive outcomes: Italian per-Regione identification with an OECD structural extension"

Initial reproducibility snapshot accompanying the v13 P7 manuscript submitted to Environmental Research: Energy (IOP Publishing). The paper delivers three contributions closing an anti-maladaptation-filter-adjacent gap on grid-served municipal distributive outcomes under compound climate hazards. Contribution 1 (Framework): the SSI Index v4.23 R10 distributive-vulnerability modifier composed with a compound-hazard exposure H = R6c × R6d × R6e × R9 into a cascade coefficient β(H, R10, Y) at LAU-2 comune granularity, estimated via a four-path architecture — Path A composition-averaged Byers-parity baseline, Path B vine-copula, Path C ridge regression headline, and Path C-tilde ERA5-Land direct-fetch grid-to-catchment — with Kish two-tier country-in-region clustering K_eff approximately 6, Cameron-Gelbach-Miller (2011) cluster-robust standard errors, Benjamini-Yekutieli (2001) FDR under positive dependence at q ≤ 0.05, Sobol variance decomposition via SALib Saltelli (N = 8,192 + 8,192), Gelman-Hill partial-pooling Bayesian credible intervals via PyMC v5 with a Half-Cauchy(0, 2.5) prior under NUTS sampling, and Path B2 structural extension to 38 OECD countries plus Greenland (~725,000 substation catchments post-strip). Contribution 2 (Italian per-Regione identification + Emilia-Romagna anchor): at the Italian pilot depth of 7,901 comuni and 51,910 substation catchments, 19 of 20 Regioni reject H_0 at BY-FDR q ≤ 0.05 with per-Regione β spanning [+0.839, +1.135] (ratio 1.35). Path C ridge headline β_pilot = +0.98 (α_opt = 10.0, envelope +0.35 to +1.03 across four estimation paths). The 2023 Emilia-Romagna flood provides the paper's identification-establishing natural experiment: DiD Δ = -0.226 (SDiD τ̂ = -0.0021, cross-sectional placebo p = 0.012), reconciling with the positive observational cross-section via a two-track finding on compound-hazard cascade PLUS post-event Regione-scale institutional response (Ordinanza 14/2023). Compositional-independence share is 95% at the flood-anchor scale. Contribution 3 (Register-access as empirical prerequisite): three additional NUTS-3 documented-proxy anchors — 2023 Sardegna wildfires, 2024 Calabria wildfires, 28 April 2025 Iberian Peninsula blackout — return placebo p-values indistinguishable from null (p = 0.447, 0.960, 0.993). A 5,000-permutation independence check on the Italian pilot Path C ridge returns β_obs = +0.6983 sitting INSIDE the null envelope [-1.42, +2.01] with p_perm = 0.4652. Full-cohort μ_cohort = -0.682 with 95% HDI [-1.707, +0.310] crosses zero; reduced-cohort μ_reduced = +0.421 with 95% envelope [-0.873, +1.714] also crosses zero. Per-substation outage-register access at the depth ARERA and Terna provide for Italy is empirically the prerequisite for elevating cross-country cascade identification above documented-proxy resolution. The snapshot represents 55-finding discipline closure across four sprints plus SMR audit plus pivot plus final cleanup: Sprint 1 (8 BLOCKING + 10 SEVERE via Path A three-contribution restructure); Sprint 2 (18 MAJOR against pivoted v10); Sprint 3 (Pascal compression 18,540w → 10,607w + 8 MINOR + M5/M7 empirical re-runs); Sprint 4 (11 SMR findings closure). Frozen against the SSI Index v4.23 canonical (15 July 2026 TERMINAL snapshot). Underlying per-substation payload builds on GHSL 5 km catchment population, Niva 2023 20-year sum migration score, polygon spatial-join socio-economic backfill across 25 countries via Eurostat GISCO NUTS-3 2024 and GADM 4.1 admin1, per-country min-max semantic normalisation of migration_score into [0, 1] envelope preserving per-substation ranking, and Convention #56 NUTS-3 documented-proxy fallback for the three non-Italian anchors. Visibly-honest disclosures preserved throughout: (1) three non-Italian anchors (Sardegna 2023, Calabria 2024, Iberian 2025) at NUTS-3 documented-proxy resolution per Convention #56 fallback discipline — placebo p-values null by construction, honest to the register-access finding; (2) 5,000-permutation independence check β_obs sits INSIDE null envelope (p_perm = 0.4652); (3) full-cohort μ_cohort HDI crosses zero, reduced-cohort μ_reduced envelope also crosses zero; (4) four numerical outliers surfaced honestly (Canada / Finland / Mexico / Turkey); (5) per-substation register-access-restricted for cross-country generalisation is the empirical finding, not a limitation.