v3 Phase B core: Team-DC + backtested ensemble, squad values

- src/lib/model/teamDc.ts: per-team attack/defence Dixon-Coles via weighted MLE
  (Maher iterations), exponential time-decay, shrinkage for thin histories,
  learned home multiplier; log-pool of score matrices. 7 vitest cases.
- buildBacktest.ts rewritten as a strict three-way-split bake-off: params
  pre-2018, tune (xi, k, w) on 2018-2022 validation, final scores on untouched
  2022-2026 test (4,448 matches). Result: ensemble RPS 0.1721 beats Elo-DC
  0.1726 and Team-DC 0.1801; ECE stays 0.01. Tuned: xi=0.5 k=5 w=0.75.
- Runtime now IS the backtested model: ratings.json carries teamDc+ensembleW;
  matchMatrix() pools both members for predictions, Monte Carlo and advance
  probs; ModelEngine re-rating preserves ensemble params; lambdas reported as
  matrix expectations (drives in-play).
- scripts/buildSquadValues.ts: Transfermarkt FIWC participants page -> all 48
  squad market values (France 1.52bn ... Qatar 20m). Display/availability layer
  only — June-2026 values are NOT in the backtested model (would leak).

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

scripts/buildSquadValues.ts

@@ -0,0 +1,58 @@
+// Transfermarkt FIWC participants page → public/data/squadvalues.json
+// One page lists all 48 squads with total + average market value — far more
+// robust than scraping 48 squad pages. Values move slowly, so this is a
+// build-time artifact (re-run data:build to refresh). Used by the squad-value
+// model layer and the team/squad UI; never overrides results-based ratings.
+import { writeFileSync, mkdirSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { dirname, join } from 'node:path';
+import { canonicalTeam, isKnownTeam } from '../src/lib/teams';
+
+const URL = 'https://www.transfermarkt.com/weltmeisterschaft/teilnehmer/pokalwettbewerb/FIWC';
+const OUT_DIR = join(dirname(fileURLToPath(import.meta.url)), '..', 'public', 'data');
+
+function euros(num: string, unit: string): number {
+  const n = Number(num);
+  return Math.round(n * (unit === 'bn' ? 1e9 : unit === 'm' ? 1e6 : 1e3));
+}
+
+async function main(): Promise<void> {
+  const res = await fetch(URL, {
+    headers: {
+      'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36',
+      'Accept-Language': 'en-US,en;q=0.9',
+    },
+    signal: AbortSignal.timeout(30_000),
+  });
+  if (!res.ok) throw new Error(`transfermarkt ${res.status}`);
+  const html = await res.text();
+
+  const out: Record<string, { totalValue: number; avgValue: number }> = {};
+  for (const tr of html.split('<tr').slice(1)) {
+    const link = tr.match(/<a[^>]*title="([^"]+)"[^>]*href="\/[a-z0-9\-]+\/startseite\/verein\/\d+"/);
+    const vals = [...tr.matchAll(/€([\d.]+)(bn|m|k)/g)].map((m) => euros(m[1]!, m[2]!));
+    if (!link || vals.length < 1) continue;
+    const team = canonicalTeam(link[1]!);
+    if (!isKnownTeam(team) || out[team]) continue; // 48 qualifiers only, first table wins
+    const totalValue = Math.max(...vals);
+    const avgValue = vals.length > 1 ? Math.min(...vals) : Math.round(totalValue / 26);
+    out[team] = { totalValue, avgValue };
+  }
+
+  const teams = Object.keys(out);
+  if (teams.length < 40) {
+    throw new Error(`only parsed ${teams.length}/48 squads — page layout may have changed; aborting (stale file kept)`);
+  }
+
+  mkdirSync(OUT_DIR, { recursive: true });
+  writeFileSync(
+    join(OUT_DIR, 'squadvalues.json'),
+    JSON.stringify({ fetchedAt: new Date().toISOString(), source: 'transfermarkt.com', teams: out }),
+  );
+  const top = teams.sort((a, b) => out[b]!.totalValue - out[a]!.totalValue).slice(0, 6)
+    .map((t) => `${t} €${(out[t]!.totalValue / 1e9).toFixed(2)}bn`).join(', ');
+  console.log(`squad values → public/data/squadvalues.json (${teams.length} teams)`);
+  console.log(`  top: ${top}`);
+}
+
+main().catch((e) => { console.error(e); process.exit(1); });