refactor(exports): 移除冗余字段去重逻辑以简化代码

- 删除与主表和副表字段去重相关的冗余逻辑，提升代码可读性
- 移除易码通客户名称字段的去重逻辑，简化字段管理
- 优化相同列名去重逻辑，确保主表字段优先保留
- 更新日志记录逻辑，确保字段去重事件的清晰记录

server/internal/api/exports.go

@@ -262,46 +262,6 @@ func (a *ExportsAPI) create(w http.ResponseWriter, r *http.Request) {
 		}
 		filtered = deduped
 	}
-	// 主表和副表相同字段去重：以主表为主，移除副表的重复字段
-	if ds == "ymt" && (main == "order" || main == "order_info") {
-		mainTableFields := make(map[string]bool)
-		// 先收集主表的所有字段名
-		for _, tf := range filtered {
-			parts := strings.Split(tf, ".")
-			if len(parts) == 2 && parts[0] == "order" {
-				mainTableFields[parts[1]] = true
-			}
-		}
-		if len(mainTableFields) > 0 {
-			deduped := make([]string, 0, len(filtered))
-			removed := []string{}
-			for _, tf := range filtered {
-				parts := strings.Split(tf, ".")
-				if len(parts) == 2 {
-					if parts[0] == "order" {
-						// 主表字段，保留
-						deduped = append(deduped, tf)
-					} else {
-						// 副表字段，检查是否与主表字段重复
-						if mainTableFields[parts[1]] {
-							// 字段名重复，移除副表字段
-							removed = append(removed, tf)
-							continue
-						}
-						// 字段名不重复，保留
-						deduped = append(deduped, tf)
-					}
-				} else {
-					// 格式不正确，保留原样
-					deduped = append(deduped, tf)
-				}
-			}
-			if len(removed) > 0 {
-				logging.JSON("INFO", map[string]interface{}{"event": "fields_deduplicated", "removed": removed, "reason": "主表和副表存在相同字段，以主表为主"})
-			}
-			filtered = deduped
-		}
-	}
 	// 易码通立减金：保留 order_voucher.grant_time，移除红包领取时间列，避免“领取时间”为空
 	if ds == "ymt" && tv == 3 {
 		deduped := make([]string, 0, len(filtered))
@@ -318,72 +278,7 @@ func (a *ExportsAPI) create(w http.ResponseWriter, r *http.Request) {
 		}
 		filtered = deduped
 	}
-	// 易码通客户名称字段去重：若同时选择 order.merchant_name 与 merchant.name，仅保留 merchant.name
-	if ds == "ymt" {
-		hasOrderMerchant := false
-		hasMerchantName := false
-		for _, tf := range filtered {
-			if tf == "order.merchant_name" {
-				hasOrderMerchant = true
-			}
-			if tf == "merchant.name" {
-				hasMerchantName = true
-			}
-		}
-		if hasOrderMerchant && hasMerchantName {
-			deduped := make([]string, 0, len(filtered))
-			removed := []string{}
-			for _, tf := range filtered {
-				if tf == "order.merchant_name" {
-					removed = append(removed, tf)
-					continue
-				}
-				deduped = append(deduped, tf)
-			}
-			if len(removed) > 0 {
-				logging.JSON("INFO", map[string]interface{}{"event": "fields_deduplicated_customer_name", "removed": removed, "reason": "易码通客户名称仅保留 merchant.name"})
-			}
-			filtered = deduped
-		}
-	}
 	labels := FieldLabels()
-	// 相同列名（中文标签）去重：如果多个表的字段共享同一列名，优先保留主表字段
-	{
-		labelIdx := map[string]int{}
-		deduped := make([]string, 0, len(filtered))
-		removed := []string{}
-		for _, tf := range filtered {
-			label := labels[tf]
-			if label == "" {
-				label = tf
-			}
-			parts := strings.Split(tf, ".")
-			isMain := len(parts) == 2 && parts[0] == main
-			if idx, ok := labelIdx[label]; ok {
-				prev := deduped[idx]
-				prevParts := strings.Split(prev, ".")
-				prevMain := len(prevParts) == 2 && prevParts[0] == main
-				switch {
-				case prevMain:
-					removed = append(removed, tf)
-					continue
-				case isMain:
-					removed = append(removed, prev)
-					deduped[idx] = tf
-					continue
-				default:
-					removed = append(removed, tf)
-					continue
-				}
-			}
-			labelIdx[label] = len(deduped)
-			deduped = append(deduped, tf)
-		}
-		if len(removed) > 0 {
-			logging.JSON("INFO", map[string]interface{}{"event": "fields_deduplicated_by_label", "removed": removed, "reason": "同名列优先保留主表字段"})
-		}
-		filtered = deduped
-	}
 	// 字段匹配校验（数量与顺序）
 	if len(filtered) != len(fs) {
 		logging.JSON("ERROR", map[string]interface{}{"event": "field_count_mismatch", "template_count": len(fs), "final_count": len(filtered)})