Fix ROOT blackboard export in Groot2 publisher

[magic-alt]

Summary

• export the shared root blackboard as ROOT when a subtree blackboard is backed by an external root blackboard
• avoid exporting duplicate ROOT payloads when multiple subtrees share the same external root blackboard
• add Groot2 logger tests for local-only blackboards, external root blackboards, and shared-root deduplication
• enable /utf-8 for behaviortree_cpp_test on MSVC so the existing Unicode name-validation tests build reliably on Windows

Validation

• conan install . -s build_type=Release --build=missing --settings:host compiler.cppstd=17 -c tools.cmake.cmaketoolchain:generator="NMake Makefiles"
• cmake --preset conan-release
• cmake --build --preset conan-release
• build/Release/tests/behaviortree_cpp_test.exe
• build/Release/tests/behaviortree_cpp_test.exe --gtest_filter=LoggerTest.Groot2Publisher_*
• pre-commit run --files src/loggers/groot2_publisher.cpp tests/CMakeLists.txt tests/gtest_loggers.cpp

Notes

• clang-tidy could not be executed in this Windows environment because the repo hook expects /bin/bash and clangd-21. The rest of the pre-commit hooks passed after re-running with SKIP=clang-tidy.

[Copilot]

Pull request overview

This PR updates the Groot2 publisher’s blackboard dump behavior so that an externally-backed root blackboard is exported as ROOT, avoids duplicate ROOT exports when multiple subtrees share the same external root, and adds logger tests covering the expected cases. It also adjusts MSVC test compilation to reliably build existing Unicode-related tests on Windows.

Changes:

• Export external root blackboard payload as ROOT when a subtree’s blackboard is backed by an external root blackboard, with deduplication across subtrees.
• Add Groot2 publisher tests for: no external root, external root export, and shared-root deduplication.
• Enable /utf-8 for the test target on MSVC and define BTCPP_GROOT_INTERFACE for conditional compilation in tests.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/loggers/groot2_publisher.cpp	Adds ROOT export + dedup logic for externally-backed root blackboards in blackboard dumps.
tests/gtest_loggers.cpp	Adds integration-style tests that request blackboard dumps over ZMQ and validate ROOT behavior.
tests/CMakeLists.txt	Ensures MSVC builds tests with UTF-8 and enables Groot2-specific test compilation when configured.

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[BlaiseLebreton]

Any news regarding this merge request ?

[magic-alt]

Any news regarding this merge request ?
Hi @BlaiseLebreton, thanks for your interest!
The PR is ready from my side — all CI checks are passing and the changes are complete. I addressed the ROOT blackboard export issue with proper deduplication and added test coverage for the key scenarios.
I'm happy to address any review feedback if the maintainers have concerns or suggestions. Looking forward to getting this merged!