refactor: 移除查bl图命令相关的注册逻辑，并在 LastDiffToImage 函数中处理头像为 nil 的情况以避免潜在错误

service/beatleader/model.go

@@ -530,16 +530,6 @@ func (p PlayerDataLite) LastDiffToImage(lastDayQueryData PlayerDataLite) string
 		log.Default().Printf("下载头像失败，url:%s,err:%v", p.Avatar, err)
 	}
 	defer os.Remove(filePath)
-	// outFile, err := util.ResizeImageByMaxHeight2File(filePath, 20)
-	// if err != nil {
-	// 	log.Default().Printf("缩放头像失败，url:%s,err:%v", p.Avatar, err)
-	// }
-	// picMsg := message.ImageMessage{
-	// 	Type: message.TypeImage,
-	// 	Data: message.ImageMessageData{
-	// 		File: outFile,
-	// 	},
-	// }
 
 	baseboard := sprite.NewNamedSpriteBoard()
 
@@ -552,6 +542,9 @@ func (p PlayerDataLite) LastDiffToImage(lastDayQueryData PlayerDataLite) string
 		Image: avatar,
 		Index: 1,
 	}
+	if avatar == nil {
+		avatarSpirit.Image = image.NewRGBA(image.Rect(0, 0, 0, 0))
+	}
 	baseboard.AddSprite(&avatarSpirit)
 
 	var sb strings.Builder