ping_pong rand() is not seeded so device ids are likely the same across nodes

Issue template

• Hardware description: docker only
• RTOS: N/A
• Installation type: a containerized version of https://micro.ros.org/docs/tutorials/core/first_application_linux/
• Version or commit hash: b86db303dd7aed7ed34de2e1c2f94300c2ba7e4e
  • this patch to fix the stack corruption https://github.com/micro-ROS/micro-ROS-demos/pull/96

Steps to reproduce the issue

Build this repo on your target

  cd /ros2_ws
  . /opt/ros/humble/setup.bash
  . install/local_setup.bash
  colcon build --packages-select micro_ros_demos_rclc
  /ros2_ws/install/micro_ros_demos_rclc/lib/micro_ros_demos_rclc/ping_pong

Expected behavior

I expect to see ping/pong messages

Actual behavior

You will see only Ping or only Pong messages

Additional information

Running on Ubuntu 24.04 host, docker compose driving a pair of containers to pubsub.

In my testing, seeding random with a nanosecond clock is sufficient to generate different device ids. I'd file a PR but I'd like to see if this was intended or maybe just an artifact of launching two container simultaneously

Beginne mit der ausführbaren Datei ping_pong im Paket micro_ros_demos_rclc und verfolge, wie seine Geräte-IDs und der Zustand von rand() initialisiert werden. Reproduziere das Problem mit den bereitgestellten colcon-Build- und Container-Befehlen und überprüfe anschließend, dass die beiden Container sowohl Ping- als auch Pong-Nachrichten mit unterschiedlichen IDs austauschen.