refactor platform logic and add gasorder domain

backend/api/internal/models/gasorder_track.go

@@ -0,0 +1,20 @@
+package models
+
+import (
+	"time"
+
+	"git.apinb.com/bsm-sdk/core/database"
+)
+
+// GasorderTrack 对应 gasorder_track，保存一次配送尝试的轨迹摘要。
+type GasorderTrack struct {
+	Entity                     // 公共实体字段
+	GasorderBasicID uint64     `gorm:"column:gasorder_basic_id;not null;index;uniqueIndex:idx_gasorder_track_attempt" json:"gasorder_basic_id"` // 订单自增主键
+	StaffAccountID  uint64     `gorm:"column:staff_account_id;not null;index" json:"staff_account_id"`                                          // 配送人员自增主键
+	AttemptNo       int        `gorm:"column:attempt_no;not null;uniqueIndex:idx_gasorder_track_attempt" json:"attempt_no"`                     // 配送尝试序号
+	StartedAt       time.Time  `gorm:"column:started_at;type:timestamptz;not null;index" json:"started_at"`                                     // 开始时间
+	CompletedAt     *time.Time `gorm:"column:completed_at;type:timestamptz" json:"completed_at"`                                                // 到达时间
+}
+
+func init()                                    { database.AppendMigrate(&GasorderTrack{}) }
+func (table *GasorderTrack) TableName() string { return "gasorder_track" }