fix: claude panic

relay/channel/claude/relay-claude.go

@@ -199,6 +199,7 @@ func responseClaude2OpenAI(reqMode int, claudeResponse *ClaudeResponse) *dto.Ope
 func claudeStreamHandler(requestMode int, modelName string, promptTokens int, c *gin.Context, resp *http.Response) (*dto.OpenAIErrorWithStatusCode, *dto.Usage) {
 	responseId := fmt.Sprintf("chatcmpl-%s", common.GetUUID())
 	var usage *dto.Usage
+	usage = &dto.Usage{}
 	responseText := ""
 	createdTime := common.GetTimestamp()
 	scanner := bufio.NewScanner(resp.Body)