perf(api): async asset ref increment via goroutine in StoreMessage

Replace synchronous BatchIncrementAssetRefs with a fire-and-forget
goroutine using context.Background() + 30s timeout, keeping the API
server fully stateless with no background workers.

Author: GenerQAQ

.github/workflows/e2e-test.yaml

@@ -47,3 +47,9 @@ jobs:
         run: |
           cd src/server
           docker compose -f docker-compose.test.yml logs
+
+      - name: Teardown
+        if: always()
+        run: |
+          cd src/server
+          docker compose -f docker-compose.test.yml down --timeout 10

src/server/api/go/cmd/server/main.go

@@ -139,5 +139,6 @@ func main() {
 	if err := srv.Shutdown(ctx); err != nil {
 		log.Sugar().Errorw("server shutdown", "err", err)
 	}
+
 	log.Sugar().Info("server exited")
 }

src/server/api/go/internal/bootstrap/container.go

@@ -215,6 +215,7 @@ func BuildContainer() *do.Injector {
 			do.MustInvoke[*blob.S3Deps](i),
 		), nil
 	})
+
 	do.Provide(inj, func(i *do.Injector) (repo.SessionRepo, error) {
 		return repo.NewSessionRepo(
 			do.MustInvoke[*gorm.DB](i),

src/server/api/go/internal/modules/service/session.go

@@ -342,10 +342,15 @@ func (s *sessionService) StoreMessage(ctx context.Context, in StoreMessageInput)
 
 	uploadedAssets = append(uploadedAssets, *asset)
 
-	// Batch increment all asset references in a single DB round-trip
-	if err := s.assetReferenceRepo.BatchIncrementAssetRefs(ctx, in.ProjectID, uploadedAssets); err != nil {
-		return nil, fmt.Errorf("batch increment asset references: %w", err)
-	}
+	// Increment asset reference counts asynchronously to avoid blocking the response.
+	go func() {
+		bgCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+		defer cancel()
+		if err := s.assetReferenceRepo.BatchIncrementAssetRefs(bgCtx, in.ProjectID, uploadedAssets); err != nil {
+			s.log.Error("async batch increment asset refs failed",
+				zap.String("project_id", in.ProjectID.String()), zap.Error(err))
+		}
+	}()
 
 	// Cache parts data in Redis after successful S3 upload
 	if s.redis != nil {