refactor: 移除冗余中间类型和不必要代码

- 移除 ScheduledTestOutcome 中间类型，RunTestBackground 直接返回 *ScheduledTestResult
- 简化 SaveResult 直接接受 *ScheduledTestResult
- 移除 handler 中不必要的 nil 检查
- 移除前端 ScheduledTestsPanel 中多余的 String() 转换

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/internal/service/account_test_service.go

@@ -1564,7 +1564,7 @@ func (s *AccountTestService) sendErrorAndEnd(c *gin.Context, errorMsg string) er
 
 // RunTestBackground executes an account test in-memory (no real HTTP client),
 // capturing SSE output via httptest.NewRecorder, then parses the result.
-func (s *AccountTestService) RunTestBackground(ctx context.Context, accountID int64, modelID string) (*ScheduledTestOutcome, error) {
+func (s *AccountTestService) RunTestBackground(ctx context.Context, accountID int64, modelID string) (*ScheduledTestResult, error) {
 	startedAt := time.Now()
 
 	w := httptest.NewRecorder()
@@ -1574,28 +1574,25 @@ func (s *AccountTestService) RunTestBackground(ctx context.Context, accountID in
 	testErr := s.TestAccountConnection(ginCtx, accountID, modelID)
 
 	finishedAt := time.Now()
-	latencyMs := finishedAt.Sub(startedAt).Milliseconds()
-
 	body := w.Body.String()
 	responseText, errMsg := parseTestSSEOutput(body)
 
-	outcome := &ScheduledTestOutcome{
-		Status:       "success",
-		ResponseText: responseText,
-		ErrorMessage: errMsg,
-		LatencyMs:    latencyMs,
-		StartedAt:    startedAt,
-		FinishedAt:   finishedAt,
-	}
-
+	status := "success"
 	if testErr != nil || errMsg != "" {
-		outcome.Status = "failed"
+		status = "failed"
 		if errMsg == "" && testErr != nil {
-			outcome.ErrorMessage = testErr.Error()
+			errMsg = testErr.Error()
 		}
 	}
 
-	return outcome, nil
+	return &ScheduledTestResult{
+		Status:       status,
+		ResponseText: responseText,
+		ErrorMessage: errMsg,
+		LatencyMs:    finishedAt.Sub(startedAt).Milliseconds(),
+		StartedAt:    startedAt,
+		FinishedAt:   finishedAt,
+	}, nil
 }
 
 // parseTestSSEOutput extracts response text and error message from captured SSE output.

backend/internal/service/scheduled_test_port.go

@@ -32,16 +32,6 @@ type ScheduledTestResult struct {
 	CreatedAt    time.Time `json:"created_at"`
 }
 
-// ScheduledTestOutcome is returned by RunTestBackground.
-type ScheduledTestOutcome struct {
-	Status       string
-	ResponseText string
-	ErrorMessage string
-	LatencyMs    int64
-	StartedAt    time.Time
-	FinishedAt   time.Time
-}
-
 // ScheduledTestPlanRepository defines the data access interface for test plans.
 type ScheduledTestPlanRepository interface {
 	Create(ctx context.Context, plan *ScheduledTestPlan) (*ScheduledTestPlan, error)

backend/internal/service/scheduled_test_runner_service.go

@@ -117,13 +117,13 @@ func (s *ScheduledTestRunnerService) runScheduled() {
 }
 
 func (s *ScheduledTestRunnerService) runOnePlan(ctx context.Context, plan *ScheduledTestPlan) {
-	outcome, err := s.accountTestSvc.RunTestBackground(ctx, plan.AccountID, plan.ModelID)
+	result, err := s.accountTestSvc.RunTestBackground(ctx, plan.AccountID, plan.ModelID)
 	if err != nil {
 		logger.LegacyPrintf("service.scheduled_test_runner", "[ScheduledTestRunner] plan=%d RunTestBackground error: %v", plan.ID, err)
 		return
 	}
 
-	if err := s.scheduledSvc.SaveResult(ctx, plan.ID, plan.MaxResults, outcome); err != nil {
+	if err := s.scheduledSvc.SaveResult(ctx, plan.ID, plan.MaxResults, result); err != nil {
 		logger.LegacyPrintf("service.scheduled_test_runner", "[ScheduledTestRunner] plan=%d SaveResult error: %v", plan.ID, err)
 	}
 

backend/internal/service/scheduled_test_service.go

@@ -77,16 +77,8 @@ func (s *ScheduledTestService) ListResults(ctx context.Context, planID int64, li
 }
 
 // SaveResult inserts a result and prunes old entries beyond maxResults.
-func (s *ScheduledTestService) SaveResult(ctx context.Context, planID int64, maxResults int, outcome *ScheduledTestOutcome) error {
-	result := &ScheduledTestResult{
-		PlanID:       planID,
-		Status:       outcome.Status,
-		ResponseText: outcome.ResponseText,
-		ErrorMessage: outcome.ErrorMessage,
-		LatencyMs:    outcome.LatencyMs,
-		StartedAt:    outcome.StartedAt,
-		FinishedAt:   outcome.FinishedAt,
-	}
+func (s *ScheduledTestService) SaveResult(ctx context.Context, planID int64, maxResults int, result *ScheduledTestResult) error {
+	result.PlanID = planID
 	if _, err := s.resultRepo.Create(ctx, result); err != nil {
 		return err
 	}