feat(worldcup): live spin-off — structural skewness law on the World Cup

Takes the law (1−2p)/√(p(1−p)) out of the paper's population: clubs → national
teams, market odds → NO odds. A results-only Elo over ~49k internationals
predicts the favourite 1X2 bet skewness for every World Cup, 1930→2026.

- skewlib/worldcup.py: martj42 loader, Elo+favourite, cuts (p_fav bucket,
  edition, phase), out-of-time forecast, scheduled fixtures, pre-registered ledger.
- skewlib/elo.py: neutral-aware HFA (backward-compatible; study --check stays green).
- analysis/41_worldcup.py: main validation → corr(predicted,realised)=+0.998 by
  p_fav bucket, crossing zero at p=½. 2022 hold-out proves the out-of-time forecast.
- analysis/predict_worldcup.py: append-only ledger (wc_predictions.json) — freezes
  each upcoming game's prediction, reconciles when the score lands.
- site /worldcup: page + interactive "next match" widget + live scorecard.

Live annex: stays out of the frozen drift-ledger (carries its own sha256+date).
Reuses the football elo/exante path (still football 1X2, national teams, no odds).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: valvesss

README.md

@@ -65,6 +65,24 @@ Every reported number regenerates from the frozen dataset (sha256 in
 for the full per-phase log and [`study/docs/METHODOLOGY.md`](study/docs/METHODOLOGY.md)
 for methods.
 
+## Annex — the World Cup, live
+
+The same law, taken **out of its own population**: from clubs to national teams,
+from market odds to **no odds at all**. A results-only Elo over ~49k internationals
+predicts the favourite-bet skewness of every World Cup from 1930 to 2026 — and
+**predicted vs realised correlate at +0.998** across favourite-probability buckets,
+crossing zero at `p = ½` exactly as `(1−2p)/√(p(1−p))` requires. A pre-registered
+ledger freezes the prediction for each upcoming match and reconciles it when the
+result lands. It updates during the 2026 tournament. Annex:
+[`study/docs/WORLDCUP.md`](study/docs/WORLDCUP.md) · page:
+[skew-dynamic.coldcodelabs.com/worldcup](https://skew-dynamic.coldcodelabs.com/worldcup).
+
+```bash
+python study/analysis/41_worldcup.py            # the analysis
+python study/analysis/export_worldcup_data.py   # regenerate the page data
+python study/analysis/predict_worldcup.py       # predict next games + reconcile ledger
+```
+
 ## The paper
 
 Working draft (RSOS target): [`study/docs/paper/draft.md`](study/docs/paper/draft.md).

site/src/components/Nav.astro

@@ -8,6 +8,7 @@ const links = [
   ['Theory', '#theory'],
   ['Timeline', '#timeline'],
   ['Reproduce', '#reproduce'],
+  ['World Cup', '/worldcup'],
 ];
 ---
 <nav class="nav">

site/src/data/wc_live.json

@@ -0,0 +1,248 @@
+{
+"meta": {
+"data_date": "2026-06-28",
+"n_played_wc": 1037,
+"n_upcoming": 15,
+"source": "martj42/international_results",
+"sha256": "df6a30676640"
+},
+"next": {
+"match_id": "2026-06-29|Brazil|Japan",
+"date": "2026-06-29",
+"home": "Brazil",
+"away": "Japan",
+"neutral": true,
+"fav_team": "Brazil",
+"fav_pick": "H",
+"p_fav": 0.556,
+"skew_pred": -0.2255,
+"win_payoff": 0.8,
+"lose_payoff": -1.0,
+"verdict": "neg"
+},
+"upcoming": [
+{
+"match_id": "2026-06-29|Brazil|Japan",
+"date": "2026-06-29",
+"home": "Brazil",
+"away": "Japan",
+"neutral": true,
+"fav_team": "Brazil",
+"fav_pick": "H",
+"p_fav": 0.556,
+"skew_pred": -0.2255,
+"win_payoff": 0.8,
+"lose_payoff": -1.0,
+"verdict": "neg"
+},
+{
+"match_id": "2026-06-29|Germany|Paraguay",
+"date": "2026-06-29",
+"home": "Germany",
+"away": "Paraguay",
+"neutral": true,
+"fav_team": "Germany",
+"fav_pick": "H",
+"p_fav": 0.6233,
+"skew_pred": -0.5087,
+"win_payoff": 0.6,
+"lose_payoff": -1.0,
+"verdict": "neg_strong"
+},
+{
+"match_id": "2026-06-29|Netherlands|Morocco",
+"date": "2026-06-29",
+"home": "Netherlands",
+"away": "Morocco",
+"neutral": true,
+"fav_team": "Netherlands",
+"fav_pick": "H",
+"p_fav": 0.4809,
+"skew_pred": 0.0764,
+"win_payoff": 1.08,
+"lose_payoff": -1.0,
+"verdict": "flat"
+},
+{
+"match_id": "2026-06-30|France|Sweden",
+"date": "2026-06-30",
+"home": "France",
+"away": "Sweden",
+"neutral": true,
+"fav_team": "France",
+"fav_pick": "H",
+"p_fav": 0.7776,
+"skew_pred": -1.3352,
+"win_payoff": 0.29,
+"lose_payoff": -1.0,
+"verdict": "neg_strong"
+},
+{
+"match_id": "2026-06-30|Ivory Coast|Norway",
+"date": "2026-06-30",
+"home": "Ivory Coast",
+"away": "Norway",
+"neutral": true,
+"fav_team": "Norway",
+"fav_pick": "A",
+"p_fav": 0.4014,
+"skew_pred": 0.4021,
+"win_payoff": 1.49,
+"lose_payoff": -1.0,
+"verdict": "pos_strong"
+},
+{
+"match_id": "2026-06-30|Mexico|Ecuador",
+"date": "2026-06-30",
+"home": "Mexico",
+"away": "Ecuador",
+"neutral": false,
+"fav_team": "Mexico",
+"fav_pick": "H",
+"p_fav": 0.5004,
+"skew_pred": -0.0017,
+"win_payoff": 1.0,
+"lose_payoff": -1.0,
+"verdict": "flat"
+},
+{
+"match_id": "2026-07-01|Belgium|Senegal",
+"date": "2026-07-01",
+"home": "Belgium",
+"away": "Senegal",
+"neutral": true,
+"fav_team": "Belgium",
+"fav_pick": "H",
+"p_fav": 0.551,
+"skew_pred": -0.205,
+"win_payoff": 0.81,
+"lose_payoff": -1.0,
+"verdict": "neg"
+},
+{
+"match_id": "2026-07-01|England|DR Congo",
+"date": "2026-07-01",
+"home": "England",
+"away": "DR Congo",
+"neutral": true,
+"fav_team": "England",
+"fav_pick": "H",
+"p_fav": 0.7811,
+"skew_pred": -1.3593,
+"win_payoff": 0.28,
+"lose_payoff": -1.0,
+"verdict": "neg_strong"
+},
+{
+"match_id": "2026-07-01|United States|Bosnia and Herzegovina",
+"date": "2026-07-01",
+"home": "United States",
+"away": "Bosnia and Herzegovina",
+"neutral": false,
+"fav_team": "United States",
+"fav_pick": "H",
+"p_fav": 0.7416,
+"skew_pred": -1.1038,
+"win_payoff": 0.35,
+"lose_payoff": -1.0,
+"verdict": "neg_strong"
+},
+{
+"match_id": "2026-07-02|Portugal|Croatia",
+"date": "2026-07-02",
+"home": "Portugal",
+"away": "Croatia",
+"neutral": true,
+"fav_team": "Portugal",
+"fav_pick": "H",
+"p_fav": 0.5381,
+"skew_pred": -0.1529,
+"win_payoff": 0.86,
+"lose_payoff": -1.0,
+"verdict": "neg"
+},
+{
+"match_id": "2026-07-02|Spain|Austria",
+"date": "2026-07-02",
+"home": "Spain",
+"away": "Austria",
+"neutral": true,
+"fav_team": "Spain",
+"fav_pick": "H",
+"p_fav": 0.7168,
+"skew_pred": -0.9623,
+"win_payoff": 0.4,
+"lose_payoff": -1.0,
+"verdict": "neg_strong"
+},
+{
+"match_id": "2026-07-02|Switzerland|Algeria",
+"date": "2026-07-02",
+"home": "Switzerland",
+"away": "Algeria",
+"neutral": true,
+"fav_team": "Switzerland",
+"fav_pick": "H",
+"p_fav": 0.4806,
+"skew_pred": 0.0777,
+"win_payoff": 1.08,
+"lose_payoff": -1.0,
+"verdict": "flat"
+},
+{
+"match_id": "2026-07-03|Argentina|Cape Verde",
+"date": "2026-07-03",
+"home": "Argentina",
+"away": "Cape Verde",
+"neutral": true,
+"fav_team": "Argentina",
+"fav_pick": "H",
+"p_fav": 0.9104,
+"skew_pred": -2.8731,
+"win_payoff": 0.1,
+"lose_payoff": -1.0,
+"verdict": "neg_strong"
+},
+{
+"match_id": "2026-07-03|Australia|Egypt",
+"date": "2026-07-03",
+"home": "Australia",
+"away": "Egypt",
+"neutral": true,
+"fav_team": "Australia",
+"fav_pick": "H",
+"p_fav": 0.4958,
+"skew_pred": 0.0168,
+"win_payoff": 1.02,
+"lose_payoff": -1.0,
+"verdict": "flat"
+},
+{
+"match_id": "2026-07-03|Colombia|Ghana",
+"date": "2026-07-03",
+"home": "Colombia",
+"away": "Ghana",
+"neutral": true,
+"fav_team": "Colombia",
+"fav_pick": "H",
+"p_fav": 0.8442,
+"skew_pred": -1.8977,
+"win_payoff": 0.18,
+"lose_payoff": -1.0,
+"verdict": "neg_strong"
+}
+],
+"backtest2026": {
+"n": 73,
+"skew_pred_pool": -0.0108,
+"skew_real_pool": -0.1236,
+"p_fav_mean": 0.6135,
+"fav_hit_rate": 0.6164,
+"brier": 0.232
+},
+"ledger": {
+"n_pending": 15,
+"n_resolved": 0
+},
+"recent_resolved": []
+}