fix(openai): do not normalize API token based accounts

backend/internal/service/openai_gateway_service.go

@@ -1937,9 +1937,11 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 	}
 	upstreamModel := billingModel
 
-	// 针对所有 OpenAI 账号执行 Codex 模型名规范化，确保上游识别一致。
+	// OpenAI OAuth 账号走 ChatGPT internal Codex endpoint，需要将模型名规范化为
+	// 上游可识别的 Codex/GPT 系列。API Key 账号则应保留原始/映射后的模型名，
+	// 以兼容自定义 base_url 的 OpenAI-compatible 上游。
 	if model, ok := reqBody["model"].(string); ok {
-		upstreamModel = normalizeCodexModel(model)
+		upstreamModel = normalizeOpenAIModelForUpstream(account, model)
 		if upstreamModel != "" && upstreamModel != model {
 			logger.LegacyPrintf("service.openai_gateway", "[OpenAI] Upstream model resolved: %s -> %s (account: %s, type: %s, isCodexCLI: %v)",
 				model, upstreamModel, account.Name, account.Type, isCodexCLI)