Add SportModeState.msg to unitree_hg for sport mode state handling

[ntrlmt]

Summary

This PR adds the missing SportModeState message to the unitree_hg package.
The message definition is based on the IDL specification provided in unitree_sdk2.

Changes

• Added unitree_hg/msg/SportModeState.msg
• Updated CMakeLists.txt to generate the message interface
• Updated package.xml to include necessary dependencies

Motivation

The unitree_hg/SportModeState message exists in unitree_sdk2, but was not available in unitree_ros2.
This PR makes it accessible in ROS 2 environments, enabling users to handle sport mode state data directly through ROS 2 interfaces.

Verification

After building the workspace:

colcon build --packages-select unitree_hg
source install/setup.bash
ros2 interface show unitree_hg/msg/SportModeState

Result:

uint32 fsm_id
uint32 fsm_mode
uint32 task_id
float32 task_time

Notes

• Tested on ROS 2 Humble
• Backward compatibility is not affected