Fix error reponses

Signed-off-by: Asai Neko <sugar@sne.moe>

data/attendance.go

@@ -228,13 +228,13 @@ func (self *Attendance) VerifyCheckinCode(checkinCode string) error {
 
 	val, err := Redis.Get(ctx, "checkin_code:"+checkinCode).Result()
 	if err != nil {
-		return errors.New("invalid or expired checkin code")
+		return errors.New("[Attendance Data] invalid or expired checkin code")
 	}
 
 	// Expected format: user_id:<uuid>:event_id:<uuid>
 	parts := strings.Split(val, ":")
 	if len(parts) != 4 {
-		return errors.New("invalid checkin code format")
+		return errors.New("[Attendance Data] invalid checkin code format")
 	}
 
 	userIdStr := parts[1]

data/client.go

@@ -87,5 +87,5 @@ func (self *Client) ValidateRedirectURI(redirectURI string) error {
 			return nil
 		}
 	}
-	return errors.New("redirect uri not match")
+	return errors.New("[Client Data] redirect uri not match")
 }