XY-850: [ELF benchmark suite] Add production ops, private corpus, and long-run scale cases

[yvette-carlisle]

Summary

• Add private production addendum, 10k backfill, guarded 100k backfill, and opt-in soak cargo-make profiles.
• Extend live-baseline reports with latency percentiles, cost proxy, resource envelope, duplicate/resume fields, and operational case guidance.
• Tighten production corpus manifest label validation so report-visible IDs stay sanitized.
• Document the opt-in/guarded paths and preserve the no-private-pass boundary without an operator-owned manifest.

Verification

• cargo make fmt
• cargo make lint-fix
• cargo make checks
• docker compose -f docker-compose.baseline.yml config >/dev/null
• cargo make baseline-production-private fail-closed without ELF_BASELINE_PRODUCTION_CORPUS_MANIFEST
• cargo make baseline-production-private-addendum fail-closed without ELF_BASELINE_PRODUCTION_CORPUS_MANIFEST
• cargo make baseline-backfill-100k-docker fail-closed without ELF_BASELINE_ENABLE_EXPENSIVE=1
• ELF_BASELINE_PRODUCTION_CORPUS_MANIFEST=apps/elf-eval/fixtures/production_corpus/synthetic_coding_agent_manifest.json ELF_BASELINE_PROJECTS=ELF ELF_BASELINE_ELF_TIMEOUT_SECONDS=1200 ELF_BASELINE_MAX_ELF_SECONDS=1200 cargo make baseline-production-private-addendum
• semantic drift audit: changed docs claims matched Makefile tasks, scripts, report output, and manifest validation
• cargo make baseline-live-docker-clean