Record XY-930 public-proxy production addendum

[yvette-carlisle]

Summary

• Add a public-safe XY-930 evidence report and JSON snapshot for the operator-approved simulated/public-proxy production corpus run.
• Update README, benchmarking evidence index, and docs log so the run is discoverable from the standard evidence surfaces.
• Add a regression test that preserves the claim boundary: this is a proxy pass through the production-private addendum path, not real private-corpus or provider-backed proof.

Benchmark

• baseline-production-private-addendum run id: live-baseline-20260619143959
• Corpus: operator-approved-public-proxy-prod-corpus-2026-06-19
• Result: 12 documents, 8 queries, 8/8 query pass, 8/8 full checks, 0 wrong_result, 0 lifecycle_fail, 0 blocked, 0 incomplete, 0 not_encoded
• Embedding mode: local / local-hash

Verification

• cargo test -p elf-eval --test real_world_job_benchmark operator_approved_public_proxy_private_addendum_preserves_boundary
• cargo make check