feat(grid_map_visualization): convert GridMapVisualization to rclcpp_lifecycle::LifecycleNode

[Lakshya-04]

Motivation

GridMapVisualization runs continuously even when no operator has RViz open, paying the full cost of deserializing every incoming GridMap message and converting it to point clouds / marker arrays for nobody. The existing implementation works around this with a 2 Hz wall timer that polls subscriber counts and lazily subscribes/unsubscribes — but this is inherently racy and adds its own timer overhead.

A lifecycle node solves this cleanly: an external lifecycle manager (e.g. nav2_lifecycle_manager, a mission controller, or a simple launch-time ros2 lifecycle set call) activates the visualization only when a human is monitoring and deactivates it when not needed.

Changes

GridMapVisualization — inherits from rclcpp_lifecycle::LifecycleNode instead of owning an internal rclcpp::Node:

• on_configure: reads parameters, constructs VisualizationFactory and all configured visualizations
• on_activate: creates the GridMap subscription and starts processing incoming maps
• on_deactivate: resets the subscription — zero CPU spent on visualization when inactive
• on_cleanup / on_shutdown: tears down visualizations and factory

Removes: activityCheckTimer_, isSubscribed_, updateSubscriptionCallback(), and the public nodePtr member.

VisualizationBase, VisualizationFactory, and all concrete visualization classes are unchanged — they accept rclcpp::Node::SharedPtr and receive one via std::static_pointer_cast from the lifecycle node.

grid_map_visualization_node.cpp — spins via get_node_base_interface() (standard lifecycle node spin pattern).

package.xml / CMakeLists.txt — add rclcpp_lifecycle dependency.

Behaviour change

The node now starts in the unconfigured state. It must be transitioned to active before it processes any messages:

ros2 lifecycle set /grid_map_visualization configure
ros2 lifecycle set /grid_map_visualization activate

Or managed automatically via nav2_lifecycle_manager in a launch file.

Test plan

• Verified node transitions correctly through configure → active → inactive → cleanup via ros2 lifecycle set
• Confirmed point cloud and occupancy grid visualizations publish when active
• Confirmed no messages are processed and no subscription exists when inactive
• Tested on ROS 2 Humble