Copy specifications and run_metadata into benchmark_results.h5

[SteSeg]

Summary

This PR makes benchmark results self‑describing by embedding the benchmark specifications and run metadata directly in benchmark_results.h5. It also includes a backfill script to update existing results files.

What’s included

• Specifications snapshot: specifications.yaml is stored inside benchmark_results.h5 after a run.
• Run metadata: a run_metadata group is written with fields like code_name, code_version, and geometry (optional nuclear data fields included for later use).
• Backfill utility: a script to update existing results in results_database/ with specs + metadata.

Where it’s implemented

• Run-time write: Benchmark._write_spec_snapshot(...) and Benchmark._write_run_metadata(...) in benchmark.py run after postprocess.
• Read helpers: BenchmarkResults.get_spec_snapshot() and BenchmarkResults.get_run_metadata() in benchmark_results.py.
• Backfill script: scripts/backfill_results_metadata.py.

Notes

• For experimental results, the backfill script skips code/nuclear data metadata.
• For OpenMC runs, code_name="openmc" and code_version is pulled from the statepoint.

[coveralls]

Coverage Report for CI Build 25938030929

Coverage increased (+0.4%) to 69.683%

Details

• Coverage increased (+0.4%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 65 coverage regressions across 2 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

65 previously-covered lines in 2 files lost coverage.

File	Lines Losing Coverage	Coverage
/usr/share/miniconda3/envs/test-env/lib/python3.12/site-packages/openmc_fusion_benchmarks/benchmark.py	48	83.6%
/usr/share/miniconda3/envs/test-env/lib/python3.12/site-packages/openmc_fusion_benchmarks/benchmark_results.py	17	81.51%

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Coverage Stats

Relevant Lines:	1735
Covered Lines:	1209
Line Coverage:	69.68%
Coverage Strength:	0.7 hits per line

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💛 - Coveralls