Validate Distributor endpoints before publication

internal/app/app.go

@@ -250,6 +250,9 @@ func GenerateDetailed(ctx context.Context, req GenerateRequest) (*ReportResult,
 		return nil, err
 	}
 	result := initialReportResult(req, resolved, PromptInspectionResult{})
+	if err := preflightDistributorNotification(req.Config); err != nil {
+		return result, err
+	}
 	outputPath, err := resolveReportOutputPath(req.WorkingDir, req.OutputPath, req.Config.Output.Directory, resolved)
 	if err != nil {
 		return result, err
@@ -302,6 +305,9 @@ func RunBatchDetailed(ctx context.Context, req BatchRequest) (*BatchResult, erro
 	if _, err := report.BatchForCommandName(string(req.Batch)); err != nil {
 		return nil, err
 	}
+	if err := preflightDistributorNotification(req.Config); err != nil {
+		return nil, err
+	}
 	outputDir, err := resolveOutputDirWithConfigured(req.WorkingDir, req.OutputDir, req.Config.Output.Directory)
 	if err != nil {
 		return nil, err
@@ -512,6 +518,16 @@ func reportNotifier(cfg config.Config, notifier Notifier) (Notifier, bool) {
 	}, true
 }
 
+func preflightDistributorNotification(cfg config.Config) error {
+	if !cfg.Notify.Distributor.Enabled {
+		return nil
+	}
+	if err := config.ValidateDistributorEndpoint(cfg.Notify.Distributor.Endpoint); err != nil {
+		return fmt.Errorf("validate notify.distributor.endpoint: %w", err)
+	}
+	return nil
+}
+
 func buildNotificationRequest(cfg config.Config, resolved report.Resolved, outputPath, runID string, generatedAt time.Time) (NotificationRequest, error) {
 	values, err := distributorTemplateValuesForReport(cfg, resolved, runID, filepath.Base(outputPath))
 	if err != nil {