feat(#94): add topic-based component discovery

[mfaferek93]

Pull Request

Summary

Add hybrid discovery that creates virtual components from topic namespaces
when ROS 2 nodes are not available (e.g., Isaac Sim publishing topics
without creating discoverable nodes).

Changes:

• Add field to Component struct (node or topic)
• Add discover_topic_namespaces() to extract namespaces from topics
• Add get_topics_for_namespace() to get topics under a namespace
• Add is_system_topic() to filter /parameter_events, /rosout, /clock
• Add discover_topic_components() to create virtual components
• Update discover_areas() to include topic-based namespaces
• Update refresh_cache() to merge node-based and topic-based components

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Issue

Link the related issue (required):

• closes Add topic-based component discovery to support systems like Isaac Sim that publish ROS 2 topics without creating standard ROS 2 nodes. #94

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Type

• Bug fix
• New feature or tests
• Breaking change
• Documentation only

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Testing

How was this tested / how should reviewers verify it?

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Checklist

• Breaking changes are clearly described (and announced in docs / changelog if needed)
• Tests were added or updated if needed
• Docs were updated if behavior or public API changed

[Copilot]

Pull request overview

This PR implements hybrid discovery that creates virtual components from topic namespaces when ROS 2 nodes are not available (e.g., Isaac Sim publishing topics without discoverable nodes). The implementation adds topic-based discovery alongside the existing node-based discovery, enabling the gateway to handle systems that publish topics without creating proper ROS 2 nodes.

Key changes:

• Adds a source field to the Component model to distinguish between "node" and "topic" based components
• Implements topic namespace discovery by extracting first-level segments from topic paths
• Merges node-based and topic-based components during cache refresh with deduplication logic

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
src/ros2_medkit_gateway/include/ros2_medkit_gateway/models.hpp	Adds source field to Component struct to distinguish discovery origin
src/ros2_medkit_gateway/include/ros2_medkit_gateway/discovery_manager.hpp	Declares discover_topic_components() and helper methods for topic-based discovery
src/ros2_medkit_gateway/include/ros2_medkit_gateway/native_topic_sampler.hpp	Declares topic namespace discovery methods and system topic filtering
src/ros2_medkit_gateway/src/discovery_manager.cpp	Implements topic-based component creation with deduplication logic
src/ros2_medkit_gateway/src/native_topic_sampler.cpp	Implements topic namespace extraction and filtering
src/ros2_medkit_gateway/src/gateway_node.cpp	Updates cache refresh to merge node-based and topic-based components
.devcontainer/devcontainer.json	Adds network=host to devcontainer run args (unrelated change)

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.