fix: use ELO change instead of win rate for best partner calculation

src/app/players/[id]/profile/page.tsx

@@ -86,12 +86,14 @@ export default async function PlayerProfilePage({ params }: PageProps) {
   const totalWins = player.wins
   const winRate = totalGames > 0 ? ((totalWins / totalGames) * 100).toFixed(1) : "0.0"
 
-  // Get best partnership
+  // Get best partnership based on ELO contribution
+  // Best partner is the one who contributed most to your rating (highest totalEloChange)
+  // Must have played at least 2 games together to be considered
   const bestPartnership = partnershipStats.reduce((best, stat) => {
-    if (stat.gamesPlayed < 3) return best // Need at least 3 games for partnership to be meaningful
-    const currentRate = stat.wins / stat.gamesPlayed
-    const bestRate = best ? best.wins / best.gamesPlayed : 0
-    return currentRate > bestRate ? stat : best
+    if (stat.gamesPlayed < 2) return best // Need at least 2 games for partnership to be meaningful
+    const currentEloChange = stat.totalEloChange
+    const bestEloChange = best ? best.totalEloChange : -Infinity
+    return currentEloChange > bestEloChange ? stat : best
   }, null as (typeof partnershipStats[0] | null))
 
   return (