fix(agent): correct serial log comment and add shutdown timeout to API server

Author: syscod3

internal/agent/api/server.go

@@ -34,7 +34,9 @@ func (s *APIServer) Start(ctx context.Context) error {
 	srv := &http.Server{Addr: ":9091", Handler: mux, ReadHeaderTimeout: 10 * time.Second}
 	go func() {
 		<-ctx.Done()
-		_ = srv.Shutdown(context.Background()) //nolint:errcheck
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		_ = srv.Shutdown(shutdownCtx) //nolint:errcheck
 	}()
 	if err := srv.ListenAndServe(); !errors.Is(err, http.ErrServerClosed) {
 		return err

internal/agent/firecracker_driver.go

@@ -220,7 +220,7 @@ func (d *FirecrackerDriver) Start(ctx context.Context, vm *impdevv1alpha1.ImpVM)
 		return 0, fmt.Errorf("open serial log %s: %w", serialLogPath, err)
 	}
 	cmd.Stdout = serialLogFile
-	defer serialLogFile.Close() //nolint:errcheck // file stays open via cmd until process exits
+	defer serialLogFile.Close() //nolint:errcheck // child inherits fd; parent closing its copy is safe
 
 	// 7. Create and start the machine.
 	m, err := firecracker.NewMachine(ctx, cfg, firecracker.WithProcessRunner(cmd))