fix(adapter): Record oss-crs timing per trial

[fuyu0425]

Summary

• Populate oss-crs build/run timing on execution results so distributed metadata no longer serializes run_time/build_time as null.
• Isolate build state by trial and explicit work_dir, including restaging benchmarks for artifact resolution when a shared explicit workdir is reused.
• Measure build time as build wall-clock minus actual flock() contention only, with regression coverage for timing and reuse paths.

Testing

• pytest -q tests/test_compose_adapter.py
• scripts/ci-tests/run-local.sh checks

Notes

• Historical trial metadata is unchanged; rerun or regenerate affected trials to backfill timing fields.
• Lock contention accounting is unit-tested via mocked timing rather than a dedicated multi-process integration test.