优化表结构，重构模型，重新实现基于白银网关的提取节点流程

web/models/bill.go

@@ -0,0 +1,34 @@
+package models
+
+import (
+	"platform/web/core"
+
+	"github.com/shopspring/decimal"
+)
+
+// Bill 账单表
+type Bill struct {
+	core.Model
+	UserID     int32           `json:"user_id" gorm:"column:user_id"`         // 用户ID
+	TradeID    *int32          `json:"trade_id" gorm:"column:trade_id"`       // 订单ID
+	ResourceID *int32          `json:"resource_id" gorm:"column:resource_id"` // 套餐ID
+	RefundID   *int32          `json:"refund_id" gorm:"column:refund_id"`     // 退款ID
+	BillNo     string          `json:"bill_no" gorm:"column:bill_no"`         // 易读账单号
+	Info       *string         `json:"info" gorm:"column:info"`               // 产品可读信息
+	Type       BillType        `json:"type" gorm:"column:type"`               // 账单类型：1-消费，2-退款，3-充值
+	Amount     decimal.Decimal `json:"amount" gorm:"column:amount"`           // 账单金额
+
+	User     *User     `json:"user" gorm:"foreignKey:UserID"`
+	Trade    *Trade    `json:"trade" gorm:"foreignKey:TradeID"`
+	Resource *Resource `json:"resource" gorm:"foreignKey:ResourceID"`
+	Refund   *Refund   `json:"refund" gorm:"foreignKey:RefundID"`
+}
+
+// BillType 账单类型枚举
+type BillType int
+
+const (
+	BillTypeConsume  BillType = 1 // 消费
+	BillTypeRefund   BillType = 2 // 退款
+	BillTypeRecharge BillType = 3 // 充值
+)