Fix TS2345 in NCAA football simulator test

Add ?? 0 fallback so optional-chained probFirst is number, not number | undefined.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/services/simulations/__tests__/ncaa-football-simulator.test.ts

@@ -90,7 +90,7 @@ describe("NCAAFootballSimulator", () => {
 
       const byId = new Map(results.map((r) => [r.participantId, r]));
       expect(byId.get("team-1")?.probabilities.probFirst).toBeGreaterThan(
-        byId.get("team-12")?.probabilities.probFirst
+        byId.get("team-12")?.probabilities.probFirst ?? 0
       );
     });