feat: add optional event-hub integration

[LimiNode]

Summary

• rename vendored dependency submodule paths from libs/* to external/*
• update log-it-cpp and time-shield-cpp submodules to current main
• add optional event-hub-cpp submodule under external/event-hub-cpp
• add CONSOLIX_USE_EVENT_HUB CMake option and compile macro
• add consolix::EventHubComponent for passive processing of event_hub::EventBus and event_hub::TaskManager from the Consolix component loop
• add a dedicated CI job and test for the optional event-hub integration

Testing notes

I could not run the build locally from this environment because direct GitHub clone/network access is unavailable here. Validation done through repository inspection and GitHub diff generation.

Current test coverage observation:

• default CI covers C++11/14/17 Linux builds and runs existing CTest tests
• currently connected tests are focused on JSON comment stripping and POSIX signal shutdown
• this PR adds coverage for EventBus queue processing, TaskManager queue processing, work-count reporting, and shutdown queue cleanup through EventHubComponent

Still not covered or only indirectly covered:

• Windows console shutdown path
• CLI/config component behavior
• ServiceLocator/AppComponentManager edge cases beyond the new integration test
• ODR tests under tests/odr, because they are present in the repo but are not currently wired into CTest