refactor platform logic and add gasorder domain

backend/api/internal/models/gasorder_payment.go

@@ -0,0 +1,15 @@
+package models
+
+import "git.apinb.com/bsm-sdk/core/database"
+
+// GasorderPayment 对应 gasorder_payment，保存订单支付尝试与统一钱包支付关联。
+type GasorderPayment struct {
+	Entity                 // 公共实体字段，Status 保存支付尝试状态
+	GasorderBasicID uint64 `gorm:"column:gasorder_basic_id;not null;index;uniqueIndex:idx_gasorder_payment_attempt" json:"gasorder_basic_id"` // 订单自增主键
+	WalletPaymentID uint64 `gorm:"column:wallet_payment_id;not null;uniqueIndex" json:"wallet_payment_id"`                                    // 钱包支付记录自增主键
+	AttemptNo       int    `gorm:"column:attempt_no;not null;uniqueIndex:idx_gasorder_payment_attempt" json:"attempt_no"`                     // 支付尝试序号
+	Amount          int64  `gorm:"column:amount;not null;check:amount > 0" json:"amount"`                                                     // 支付金额，单位分
+}
+
+func init()                                      { database.AppendMigrate(&GasorderPayment{}) }
+func (table *GasorderPayment) TableName() string { return "gasorder_payment" }