Fix ROS 2 controller bounds and shutdown

[wee733]

Summary

• Fix out-of-bounds writes when publishing the seven-element joint position, velocity, and current arrays.
• Bound copies by both the ROS message array size and the SDK vector size.
• Avoid releasing the hardware interface from a global shutdown callback while the 1 kHz state timer may still be active.

Problem

RobotStatus.msg defines seven-element joint arrays, but the controller loops previously used i <= 7, which writes index 7 and invokes undefined behavior.

The controller also registered an on_shutdown callback that immediately reset interfaces_ptr_. During a Ctrl+C shutdown this could race with PubState(), which accesses the same pointer every millisecond. On the tested system, the motor and CAN cleanup ran, but the process then exited with code -11.

Relying on normal node/member destruction stops executor callbacks before releasing the hardware interface. After this change, the receiver thread and CAN socket terminate cleanly and the process exits normally.

Validation

• Ubuntu 24.04, ROS 2 Jazzy, x86_64
• Real ARX R5 connected through can1
• colcon build --symlink-install --packages-select arx_r5_controller
• /arm_status received at approximately 1000 Hz
• SocketCAN reported zero bus errors and dropped frames
• Repeated launch and Ctrl+C shutdown completed cleanly

The official documentation targets ROS 2 Humble; maintainers should also verify the lifecycle change on Humble.

[Copilot]

Pull request overview

This PR fixes undefined behavior in the ROS 2 R5 controller’s status publishing by preventing out-of-bounds writes to the 7-element joint arrays, and it removes a shutdown callback that could race with the 1 kHz publish timer and cause crashes during Ctrl+C shutdown.

Changes:

• Replace incorrect joint array loops (previously iterating with i <= 7) with bounds-checked loops using both the ROS message array size and the SDK vector size.
• Remove rclcpp::on_shutdown(...) callback that reset interfaces_ptr_, avoiding a potential race with timer callbacks during shutdown.

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