Adds the NBA_20 bracket template (20-team structure with play-in
tournament) and rewrites the NBA simulator to be bracket-aware like UCL.
- Add NBA_20 bracket template: PIR1 (4) → PIR2 (2) → First Round (8)
→ Conference Semifinals → Conference Finals → NBA Finals
- Add participantLabels (East/West 1–10) for admin bracket UI slot labels
- Add generateNBA20Bracket and advanceNBAPlayInWinner in playoff-match.ts
with custom play-in advancement logic (PIR1 winners go to two different
destinations)
- Rewrite NBASimulator with two auto-detected modes:
- Bracket-aware (preferred): reads actual bracket state, simulates only
remaining rounds forward using 50k Monte Carlo iterations
- Season-projection (fallback): existing logic for pre-playoff use
- Guard resolveGame/resolveSeries against null participants (throws with
match ID and slot info instead of silently using empty string)
- Document load-bearing First Round match ordering in generateNBA20Bracket
- Add 25 unit tests covering Elo math, team data, template structure,
and all simulator integration paths
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>