all the refactor

pkg/actor/grpc_server.go

@@ -284,9 +284,14 @@ func NewControlServer[V any](config ServerConfig, pool GrainPool[V]) (*grpc.Serv
 	reflection.Register(grpcServer)
 
 	log.Printf("gRPC server listening as %s on %s", pool.Hostname(), config.Addr)
+	// Serve runs in a goroutine because it blocks until the listener is closed.
+	// On Serve error we log it instead of crashing the whole process from deep
+	// inside this package — the caller (composition root) should rely on
+	// process supervision (Kubernetes) to restart, or check gRPC health via the
+	// pool after this returns.
 	go func() {
 		if err := grpcServer.Serve(lis); err != nil {
-			log.Fatalf("failed to serve gRPC: %v", err)
+			log.Printf("gRPC server %s serve error: %v", config.Addr, err)
 		}
 	}()