feat: wire up CLI export/import to HDF5, add BH benchmark baselines (… #2

	name: Benchmark Smoke

	on:
	push:
	branches: [main, master]
	paths:
	- 'benchmarks/**'
	- 'include/nbody/performance_observability.hpp'
	- 'src/utils/performance_observability.cpp'
	- 'include/nbody/serialization.hpp'
	- 'src/utils/serialization.cpp'
	- 'scripts/benchmark.sh'
	- 'CMakeLists.txt'
	pull_request:
	branches: [main, master]
	paths:
	- 'benchmarks/**'
	- 'include/nbody/performance_observability.hpp'
	- 'src/utils/performance_observability.cpp'
	- 'include/nbody/serialization.hpp'
	- 'src/utils/serialization.cpp'
	- 'scripts/benchmark.sh'
	- 'CMakeLists.txt'
	workflow_dispatch:

	permissions:
	contents: read

	jobs:
	serialization-smoke:
	name: Serialization Benchmark Smoke
	runs-on: ubuntu-latest
	env:
	FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true
	NBODY_BENCHMARK_PARTICLES: 256
	NBODY_BENCHMARK_ITERATIONS: 2
	steps:
	- name: Checkout
	uses: actions/checkout@v6

	- name: Configure headless benchmark build
	run: \|
	cmake -S . -B build/benchmark-smoke \
	-DNBODY_ENABLE_RENDERING=OFF \
	-DNBODY_ENABLE_CUDA=OFF \
	-DNBODY_BUILD_TESTS=ON \
	-DNBODY_BUILD_EXAMPLES=OFF \
	-DNBODY_BUILD_BENCHMARKS=ON \
	-DNBODY_ENABLE_PROFILING=ON \
	-G "Unix Makefiles"

	- name: Build benchmark target
	run: cmake --build build/benchmark-smoke --target nbody_benchmarks -j"$(nproc)"

	- name: Run benchmark smoke
	run: \|
	mkdir -p build
	cp build/benchmark-smoke/nbody_benchmarks build/nbody_benchmarks
	./scripts/benchmark.sh serialization.round_trip build/benchmark-smoke/results.json

	- name: Show benchmark result
	run: cat build/benchmark-smoke/results.json

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