refactor platform logic and add gasorder domain

backend/api/internal/models/gasorder_assign.go

@@ -0,0 +1,23 @@
+package models
+
+import (
+	"time"
+
+	"git.apinb.com/bsm-sdk/core/database"
+)
+
+// GasorderAssign 对应 gasorder_assign，保存订单履约分配历史。
+type GasorderAssign struct {
+	Entity                     // 公共实体字段
+	GasorderBasicID  uint64    `gorm:"column:gasorder_basic_id;not null;index" json:"gasorder_basic_id"`                       // 订单自增主键
+	GasBasicID       uint64    `gorm:"column:gas_basic_id;not null;index" json:"gas_basic_id"`                                 // 气站自增主键
+	DeliveryBasicID  uint64    `gorm:"column:delivery_basic_id;not null;index" json:"delivery_basic_id"`                       // 配送点自增主键
+	StaffAccountID   uint64    `gorm:"column:staff_account_id;not null;index" json:"staff_account_id"`                         // 配送人员自增主键
+	AssignerIdentity string    `gorm:"column:assigner_identity;type:varchar(36);not null;default:''" json:"assigner_identity"` // 分配人标识
+	AssignerName     string    `gorm:"column:assigner_name;type:varchar(64);not null;default:''" json:"assigner_name"`         // 分配人姓名快照
+	AssignedAt       time.Time `gorm:"column:assigned_at;type:timestamptz;not null;index" json:"assigned_at"`                  // 分配时间
+	Reason           string    `gorm:"column:reason;type:text;not null;default:''" json:"reason"`                              // 分配原因
+}
+
+func init()                                     { database.AppendMigrate(&GasorderAssign{}) }
+func (table *GasorderAssign) TableName() string { return "gasorder_assign" }