XY-842: [ELF benchmark vNext] Implement real_world_job fixture schema and report publisher

[yvette-carlisle]

Summary

• Add the real_world_job_benchmark run/publish CLI for elf.real_world_job/v1 fixtures and elf.real_world_job_report/v1 JSON reports.
• Add one checked-in work_resume smoke fixture plus integration tests for JSON and Markdown report generation.
• Add cargo make real-world-job-smoke and docs that keep real-world job reports separate from live-baseline claims.

Verification

• cargo make fmt
• cargo make lint-fix
• cargo make real-world-job-smoke (artifacts: tmp/real-world-job/real-world-job-smoke-report.json, tmp/real-world-job/real-world-job-smoke-report.md)
• cargo test -p elf-eval --test real_world_job_benchmark --all-features
• cargo make checks