SLAM-009: Implement and Publish Robot Pose Output

[lblommesteyn]

Summary

• update slam_bridge_node to publish /slam_pose as geometry_msgs/msg/PoseWithCovarianceStamped
• publish /slam_pose at a fixed configurable rate (slam_pose_publish_rate_hz, default 20.0, minimum enforced 10.0)
• publish /slam_pose in configurable frame (slam_pose_frame, default map)
• preserve incoming covariance when available and inject fallback non-zero covariance when input covariance is all zeros
• transform pose and covariance to target frame when source frame differs
• add periodic frequency logging for /slam_pose publication (slam_pose_frequency_log_interval_sec)
• add launch arguments to configure /slam_pose topic/frame/rate from mapping_pipeline.launch.py
• configure default Kitware params with odometry_frame: map and pose output frequency 20.0
• update README with /slam_pose output contract and launch usage

Validation

• Python syntax checks passed for updated nodes and launch file
• package.xml is well-formed XML
• kitware_slam_params.yaml parses successfully
• static config/code checks confirm:
  • /slam_pose type: PoseWithCovarianceStamped
  • target frame default: map
  • publish rate default: 20.0 Hz with minimum guard at 10.0 Hz
  • covariance fallback path is non-zero

[lblommesteyn]

Triage note from AP1 bringup: this looks foundational for the current mapping pipeline behavior. The local AP1 bringup relied on slam_bridge publishing pose/distance and the stored point registry existing, so if this functionality is not already effectively on main, it should be reviewed/merged before deeper SLAM testing.