fix(locomo): attest durable visible versions

[fazpu]

Summary

Make LoCoMo isolation attest durable uploaded versions through the public documents_live → document_versions_visible join instead of treating documents_live.current_version_id as an upload pointer. Update the binding benchmark contract, operator recovery wording, and focused regression coverage.

Problem and important decision

A fresh full-v10 run uploaded a session and checkpointed the returned version, then failed before the next upload. The previous query parsed documents_live.current_version_id as mandatory. That field is intentionally a readiness pointer: it remains null until structure processing publishes ready content. It is therefore not the authority for durable upload identity.

The exact public join now selects (deployment_id, source_ref, doc_id, version_id) from documents_live and document_versions_visible, with both deployment_id and doc_id in the join predicate. Exact set equality still rejects extra, replaced, tombstoned, or cross-deployment state. No direct database access, RLS, retry loop, or readiness wait is added.

Sources inspected

• plan/designs/locomo_benchmark_design.md pre-run isolation contract
• src/rememberstack/spine/migrations/versions/p9_01_0022_memory_v1_query_space.py semantics of documents_live and document_versions_visible
• src/rememberstack/spine/document_catalog.py readiness publication of current_version_id
• the live fresh Compose query results after two durable LoCoMo uploads

Validation and review

• Four focused benchmark isolation/recovery tests passed
• Live visible-version attestation passed against two durable partial checkpoints while the readiness pointer was not authoritative
• Ruff check and format check passed
• Pyright: 0 errors
• git diff --check passed
• Full suite remains delegated to CI; no answer/judge call was made

Limitations and follow-up

The current partial run is revision-pinned and will not be forced forward. After merge, build the exact merged main image and prepare a new run directory. Prior empty/partial benchmark state is disposable.

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