[codex] Hosted review phase 4 metadata and provenance

[CompleteDotTech]

Hosted Review Phase 4 PR Notes

Linked issues

Fixes OpenCoven#105.
Fixes OpenCoven#106.
Fixes OpenCoven#112.

Summary

• Extends AGENTS.md frontmatter with enforceable hosted metadata: stable id, trust, visibility, source, source_ref, expiry, created_at, created_by, session_id, transcript_ref, and confidence.
• Enforces hosted memory metadata during loading: missing trust is lowest trust, expired memory is ignored, security-private memory is excluded from public hosted review, and trust must meet the configured threshold.
• Renders hosted memory as tagged entries with stable ids, trust, visibility, source, source_ref, and session metadata so review output can cite memory refs.
• Threads session-scoped provenance into hosted auto-extracted memory candidates.
• Adds structured review-output parsing and validation helpers for memory_refs on memory-dependent findings.
• Documents the hosted frontmatter contract and citation behavior.

Test evidence

• cargo fmt --all -- --check
• cargo check --workspace
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test -p claurst-core --lib claudemd --quiet
• cargo test -p claurst-core --lib system_prompt --quiet
• cargo test -p claurst-core --lib --quiet
• cargo test -p claurst-query session_memory --quiet
• cargo test -p claurst-commands structured_review_output --quiet
• cargo test --workspace --quiet

Risk notes

• The slash /review command remains markdown-first; the structured review parser is available for hosted integrations that request JSON review artifacts.
• Hosted memory without trust metadata is intentionally ignored unless policy lowers the trust threshold.
• Provenance stores references and ids, not secret values.