feat: Implement CMake macro for registering nodes with CallbackIsolatedExecutor

[atsushi421]

Summary

rclcpp_components_register_nodes() is a CMake macro for registering composable nodes with rclcpp_components::ComponentManager. However, when using CallbackIsolatedExecutor (CIE), a dedicated container (component_container_callback_isolated) must be used, and there is currently no way to specify the executor type at node registration time.

By providing a CIE-specific CMake macro, users can declaratively specify which executor to use when registering composable nodes.

Motivation

Current workflow:

1. Register composable nodes with rclcpp_components_register_nodes()
2. Manually specify component_container_callback_isolated in the launch file

This approach has the following issues:

• No consistency guarantee between CMakeLists.txt and launch files: Since executor specification is separated between node registration and runtime, nodes may unintentionally run with the wrong executor
• Usability: The configuration steps required to use CIE are scattered, making it difficult for new users to set up correctly

Proposed API

# Option 1: Wrapper around rclcpp_components_register_nodes
cie_register_nodes(<target> <node_class_name>)

# Option 2: Generic macro with executor as an argument
cie_components_register_node(<target>
  PLUGIN <node_class_name>
  EXECUTOR callback_isolated  # or "single"
)

Scope

• Implement CMake macro/function (.cmake file)
• Export from callback_isolated_executor package
• Update documentation and samples (migrate cie_sample_application's CMakeLists.txt to the new macro)

References

• rclcpp_components_register_nodes: Existing implementation for reference