Implement asynchronous AI recommendation cache refresh in company service

- Introduced `refreshAIRecommendationsCacheAsync` method to refresh AI recommendations in the background, improving responsiveness by serving the previous cache until the refresh completes.
- Updated `StartAIOnboarding` to call the new asynchronous cache refresh method instead of invalidating the cache directly.
- Added logging for cache refresh operations, including success and error handling, to enhance observability.

This update enhances the AI recommendation caching mechanism, providing a smoother onboarding experience and reducing latency in recommendation retrieval.

internal/company/recommendation.go

@@ -85,7 +85,8 @@ func (s *companyService) StartAIOnboarding(ctx context.Context, companyID string
 		return nil, fmt.Errorf("failed to start AI onboarding: %w", err)
 	}
 
-	s.invalidateAIRecommendationCache(ctx, companyID)
+	// Prefetch recommendations in the background; keep serving the previous cache until refresh completes.
+	s.refreshAIRecommendationsCacheAsync(companyID)
 
 	return &OnboardingResponse{Status: result.Status}, nil
 }
@@ -143,6 +144,48 @@ func (s *companyService) GetAIRecommendations(ctx context.Context, companyID str
 		return nil, errors.New("company not found")
 	}
 
+	return s.fetchAndCacheAIRecommendations(ctx, companyID)
+}
+
+func (s *companyService) refreshAIRecommendationsCacheAsync(companyID string) {
+	if s.aiRecommendationClient == nil {
+		return
+	}
+
+	companyID = strings.TrimSpace(companyID)
+	if companyID == "" {
+		return
+	}
+
+	go func() {
+		ctx := context.Background()
+		s.logger.Info("Refreshing AI recommendation cache in background", map[string]interface{}{
+			"company_id": companyID,
+		})
+
+		if _, err := s.repository.GetByID(ctx, companyID); err != nil {
+			s.logger.Error("Failed to load company for AI recommendation refresh", map[string]interface{}{
+				"company_id": companyID,
+				"error":      err.Error(),
+			})
+			return
+		}
+
+		if _, err := s.fetchAndCacheAIRecommendations(ctx, companyID); err != nil {
+			s.logger.Error("Failed to refresh AI recommendation cache", map[string]interface{}{
+				"company_id": companyID,
+				"error":      err.Error(),
+			})
+			return
+		}
+
+		s.logger.Info("AI recommendation cache refreshed", map[string]interface{}{
+			"company_id": companyID,
+		})
+	}()
+}
+
+func (s *companyService) fetchAndCacheAIRecommendations(ctx context.Context, companyID string) ([]RecommendedTenderResponse, error) {
 	s.logger.Info("Fetching AI tender recommendations", map[string]interface{}{
 		"company_id": companyID,
 	})
@@ -228,19 +271,6 @@ func (s *companyService) cacheAIRecommendations(ctx context.Context, companyID s
 	}
 }
 
-func (s *companyService) invalidateAIRecommendationCache(ctx context.Context, companyID string) {
-	if s.redisClient == nil || s.recommendationCacheTTL <= 0 {
-		return
-	}
-
-	if err := s.redisClient.Del(ctx, aiRecommendationCacheKey(companyID)); err != nil {
-		s.logger.Warn("Failed to invalidate AI recommendation cache", map[string]interface{}{
-			"company_id": companyID,
-			"error":      err.Error(),
-		})
-	}
-}
-
 func (s *companyService) buildOnboardingDocuments(fileIDs []string) (string, error) {
 	if len(fileIDs) == 0 {
 		return "[]", nil