WC2026 group advancement probabilities (Monte Carlo)

Per-team probability of finishing 1st/2nd/3rd/4th in one group, from a 10,000-iteration Monte Carlo over the remaining fixtures anchored on the current standings. p_advance = p_1st + p_2nd; p_third_contention is the raw P(3rd) (cross-group best-third resolution lives in /v1/formulas/wc2026/progression). Response object keys: group, iterations, matches_played, matches_remaining, teams[] (team {id, name, elo}, current {played, points, gd}, p_1st, p_2nd, p_3rd, p_4th, p_advance, p_third_contention, p_eliminated), as_of. 1-hour Redis cache.