Add existing ROS 2 robot hardware provider

[temiroff]

Outcome

• configure robots already running ROS 2 through a read-only ROSBridge provider
• report confirmed live ROS topics and capabilities while keeping motion disarmed
• preserve the vendor ROS stack and use a non-exclusive connection during deployments
• add safe multi-robot manifest/config support for the existing ROS 2 provider
• bump blacknode-robot to 0.5.3

Verification

• $env:PYTHONPATH='E:\F\PROJECTS\NVDIA\Blacknode\python'; python -m pytest -q
• 134 passed, 2 skipped

Managed Runtime release decision

No blacknode-runtime release is required. This is an extension-package implementation delivered through the managed Hardware package/update surface. The Blacknode core source lock will be updated after this PR merges so Devices -> Software -> Check updates -> Update all can deliver the merged Hardware commit.