feat: publish notable fight results to Nostr relays

NIP-01 kind:1 notes posted for KOs, perfects, upsets, and big Elo
swings. Includes bot names, Elo changes, arena, and replay link.
Configurable via BOTFIGHTS_NOSTR_RELAYS and BOTFIGHTS_NOSTR_NSEC env
vars. Silently skips if NSEC not set.

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

server/src/engine/orchestrator.ts

@@ -11,6 +11,7 @@ import { setCooldown } from './queue.js'
 import { isHumanPlayer, waitForHumanResponse } from './human-responses.js'
 import { payWinner, refundEntry, ENTRY_FEE_SATS } from './payments.js'
 import { settleBets, lockBets } from './betting.js'
+import { publishFightResult } from './nostr-publish.js'
 
 interface BotRecord {
   id: string
@@ -333,12 +334,14 @@ async function executeFightRounds(fightId: string, botA: BotRecord, botB: BotRec
   let comboA = 0
   let comboB = 0
   let winnerId: string | null = null
+  let lastRound = 0
   const usedTypes = new Set<string>()
 
   // Pick a random round for retro mode (rounds 3-8, ensuring it's not too early or late)
   const retroRound = 3 + Math.floor(Math.random() * Math.min(6, MAX_ROUNDS - 4))
 
   for (let round = 1; round <= MAX_ROUNDS; round++) {
+    lastRound = round
     const challenge = round === retroRound
       ? generateRetroChallenge()
       : pickChallenge(usedTypes, arena.modifier)
@@ -447,6 +450,10 @@ async function executeFightRounds(fightId: string, botA: BotRecord, botB: BotRec
   // Finalize fight + update bot stats atomically
   const isMockFight = isMockBot(botA.webhookUrl) || isMockBot(botB.webhookUrl) || isClassicBot(botA.webhookUrl) || isClassicBot(botB.webhookUrl)
   const kFactor = isMockFight ? 12 : 32 // Dampened Elo for mock/classic fights
+  let winnerEloChange = 0
+  let loserEloChange = 0
+  let newWinnerEloFinal = 0
+  let newLoserEloFinal = 0
 
   const finalize = sqlite.transaction(() => {
     // Mark fight finished
@@ -463,6 +470,10 @@ async function executeFightRounds(fightId: string, botA: BotRecord, botB: BotRec
       const loser = winnerId === botA.id ? botB : botA
 
       const { newWinnerElo, newLoserElo } = calculateElo(winner.eloRating, loser.eloRating, kFactor)
+      winnerEloChange = Math.round(newWinnerElo - winner.eloRating)
+      loserEloChange = Math.round(newLoserElo - loser.eloRating)
+      newWinnerEloFinal = newWinnerElo
+      newLoserEloFinal = newLoserElo
       const newWinStreak = winner.winStreak + 1
       const newBestStreak = Math.max(winner.bestStreak, newWinStreak)
 
@@ -510,6 +521,21 @@ async function executeFightRounds(fightId: string, botA: BotRecord, botB: BotRec
     potSats: mode === 'ranked' ? 42 : 0,
   })
 
+  // Publish notable results to Nostr
+  if (winnerId) {
+    const winner = winnerId === botA.id ? botA : botB
+    const loser = winnerId === botA.id ? botB : botA
+    const isUpset = loser.eloRating - winner.eloRating > 150
+    const isKO = (winnerId === botA.id && hpB <= 0) || (winnerId === botB.id && hpA <= 0)
+    publishFightResult({
+      fightId, winnerName: winner.name, loserName: loser.name, winnerId,
+      winnerElo: newWinnerEloFinal, loserElo: newLoserEloFinal,
+      winnerEloChange, loserEloChange,
+      isPerfect: !!isPerfect, isKO, isUpset,
+      totalRounds: lastRound, arena: arena.name,
+    }).catch(err => console.warn('[nostr] publish failed:', err))
+  }
+
   // Settle bets
   try {
     const settlements = await settleBets(fightId, winnerId)