feat: 完善平台总后台模块

backend/api/internal/models/user_service_relation.go

@@ -0,0 +1,15 @@
+package models
+
+import "git.apinb.com/bsm-sdk/core/database"
+
+// UserServiceRelation 对应 user_service_relation，保存用户服务归属快照。
+type UserServiceRelation struct {
+	Entity
+	UserAccountID   uint64 `gorm:"column:user_account_id;not null;index" json:"user_account_id"`
+	GasBasicID      uint64 `gorm:"column:gas_basic_id;not null;default:0;index" json:"gas_basic_id"`
+	DeliveryBasicID uint64 `gorm:"column:delivery_basic_id;not null;default:0;index" json:"delivery_basic_id"`
+	StaffAccountID  uint64 `gorm:"column:staff_account_id;not null;default:0;index" json:"staff_account_id"`
+}
+
+func init()                                          { database.AppendMigrate(&UserServiceRelation{}) }
+func (table *UserServiceRelation) TableName() string { return "user_service_relation" }