refactor: 清理 PositionPollingService 代码

- 移除多余的空行
- 移除调试日志

backend/src/main/kotlin/com/wrbug/polymarketbot/service/accounts/PositionPollingService.kt

@@ -139,8 +139,6 @@ class PositionPollingService(
                                     logger.error("通知订阅者失败: ${e.message}", e)
                                 }
                             }
-                            
-                            logger.debug("发布仓位数据事件: currentPositions=${positions.currentPositions.size}, historyPositions=${positions.historyPositions.size}, subscribers=${currentSubscribers.size}")
                         } catch (e: Exception) {
                             logger.error("分发仓位数据事件失败: ${e.message}", e)
                         }

backend/src/main/kotlin/com/wrbug/polymarketbot/service/copytrading/monitor/OnChainWsService.kt

@@ -1,5 +1,7 @@
 package com.wrbug.polymarketbot.service.copytrading.monitor
 
+import com.github.benmanes.caffeine.cache.Cache
+import com.github.benmanes.caffeine.cache.Caffeine
 import com.google.gson.JsonNull
 import com.wrbug.polymarketbot.api.*
 import com.wrbug.polymarketbot.entity.Leader
@@ -12,6 +14,7 @@ import okhttp3.OkHttpClient
 import org.slf4j.LoggerFactory
 import org.springframework.stereotype.Service
 import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.TimeUnit
 
 /**
  * 链上 WebSocket 监听服务
@@ -30,6 +33,11 @@ class OnChainWsService(
     // 存储需要监听的Leader：leaderId -> Leader
     private val monitoredLeaders = ConcurrentHashMap<Long, Leader>()
 
+    // 存储已处理的交易哈希，用于去重（LRU 缓存，保留最近 100 条）
+    private val processedTxHashes: Cache<String, Long> = Caffeine.newBuilder()
+        .maximumSize(100)
+        .build()
+
     /**
      * 启动链上 WebSocket 监听
      * 通过统一服务订阅所有 Leader
@@ -95,6 +103,14 @@ class OnChainWsService(
     ) {
         val leader = monitoredLeaders[leaderId] ?: return
 
+        // 根据 txHash 去重（使用原子操作避免竞态条件）
+        val currentTime = System.currentTimeMillis()
+        val existingTimestamp = processedTxHashes.asMap().putIfAbsent(txHash, currentTime)
+        if (existingTimestamp != null) {
+            logger.debug("交易已处理过，跳过: leaderId=$leaderId, txHash=$txHash, firstProcessedAt=$existingTimestamp")
+            return
+        }
+
         logger.debug("开始处理 Leader 交易: leaderId=$leaderId, txHash=$txHash, leaderAddress=${leader.leaderAddress}")
 
         try {