v3: Model-vs-Market scoreboard — frozen forecasts, fair scoring, live page

- prediction_snapshots: model + de-vigged market frozen ≤15min pre-kickoff
  (or at first sight of a live match, flagged 'late' and excluded from totals).
- src/lib/model/scoring.ts: ONE shared RPS/Brier/log-loss implementation for
  the backtest and the live scoreboard.
- /api/scoreboard + /scoreboard page: per-match model-vs-bookmaker bars, RPS
  for both after FT, 'closer' badges, running head-to-head with honest rules
  printed (small-sample caveat included). Nav: 'vs Market'.
- Methodology page now shows the three-way split + ensemble bake-off variants.
- Verified end-to-end with a simulated match: snapshot froze model 80.7% and
  DraftKings 67.0% (de-vig correct), both scored at FT, late-flag honored.

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

server/src/ingest/scheduler.ts

@@ -23,7 +23,11 @@ function dateUTC(iso: string): string {
   return `${d.getUTCFullYear()}${String(d.getUTCMonth() + 1).padStart(2, '0')}${String(d.getUTCDate()).padStart(2, '0')}`;
 }
 
-export function startScheduler(state: TournamentState, onChange: () => void): () => void {
+export function startScheduler(
+  state: TournamentState,
+  onChange: () => void,
+  onTick?: () => void,
+): () => void {
   const token = process.env.FOOTBALL_DATA_TOKEN?.trim();
   const sofa = process.env.ENABLE_SOFASCORE === 'true';
   let stopped = false;
@@ -88,6 +92,7 @@ export function startScheduler(state: TournamentState, onChange: () => void): ()
       const changed = state.mergeLive(matches, source);
       if (changed.length) { console.log(`[ingest] ${changed.length} fixture(s) updated via ${source}`); onChange(); }
     }
+    onTick?.(); // e.g. freeze pre-kickoff forecast snapshots
 
     // Keep live matches' stats + event timeline fresh at the live cadence.
     for (const f of state.allFixtures()) {