feat: 重构消息处理模块，引入统一的消息接口和类型安全的消息解析

handler/auth/auth.go

@@ -8,6 +8,7 @@ import (
 	"git.lxtend.com/qqbot/auth"
 	"git.lxtend.com/qqbot/constants"
 	"git.lxtend.com/qqbot/handler"
+	"git.lxtend.com/qqbot/message"
 	"git.lxtend.com/qqbot/model"
 )
 
@@ -36,8 +37,9 @@ func setUserLevel(msg model.Message) (reply model.Reply) {
 		}
 	}
 	userText := tokens[1]
-	if userId, err := model.ParseAtMessage(userText); err == nil {
-		userText = userId.Data.QQ
+	atMsg := message.AtMessage{}
+	if err := atMsg.ParseMessage(userText); err == nil {
+		userText = atMsg.Data.QQ
 	}
 	log.Println(userText)
 	user, err := strconv.Atoi(userText)