Date format Handling from JSON to BSON using GO

my demo code

	collection := db.Collection(UserFCardLog{}.CollectionName())
	logData := UserFCardLog{
		Change:     100,
		Day:        "2025-08-26",
		New:        1100,
		Old:        1000,
		SceneType:  "battle",
		SceneValue: "level-5",
		Sec:        time.Now().Unix(),
		Type:       1,
		UserID:     12345,
		CreateAt:   time.Now().UTC(),
	}

	result, err := collection.InsertOne(ctx, logData)
	if err != nil {
		log.Fatal("insert fail:", err)
	}
	log.Println("insert success, ID:", result.InsertedID)