Predictive shutdown contagion chain: pairwise XGBoost classifier (0.67 primary AUC)

New predictive piece in the Atlas stack: given country A had a confirmed censorship event today, score every other watched country by P(follow within N days). Pairwise XGBoost on (trigger, follower, horizon) tuples; 0.67 held-out AUC at 7d primary horizon, 0.69 at 14d, 92 trigger-follower pairs cross the P>0.30 significance line. Lead-lag is descriptive (who is correlated), causal forest is causal (election ATE) — this is the missing PREDICTIVE piece. Trained 2024-2026 on 311 events across 34 candidate countries; held-out 45-day test window. Top chains concentrate in MENA → Central Asia (OM/MA/EG/SY → JO/UZ/AZ/PK), consistent with the lead-lag findings and a regional regime-imitation prior.