feat: tournament engine with single-elimination brackets

Create, join, seed by Elo, generate bracket matches with byes,
advance rounds on fight completion, finish tournament on champion.
Wire into orchestrator fight finalization.

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

server/src/engine/orchestrator.ts

@@ -13,6 +13,7 @@ import { payWinner, refundEntry, ENTRY_FEE_SATS } from './payments.js'
 import { settleBets, lockBets } from './betting.js'
 import { publishFightResult } from './nostr-publish.js'
 import { getCurrentSeason } from './seasons.js'
+import { onFightFinished as onTournamentFightFinished } from './tournaments.js'
 
 interface BotRecord {
   id: string
@@ -514,6 +515,9 @@ async function executeFightRounds(fightId: string, botA: BotRecord, botB: BotRec
 
   finalize()
 
+  // Advance tournament bracket if this was a tournament match
+  try { onTournamentFightFinished(fightId, winnerId ?? null) } catch { /* not a tournament fight */ }
+
   emit(fightId, 'fight_end', {
     winnerId,
     winnerName,