[codex] Allow session-relative freshness refs

[8Dionysus]

What changed

• Treat needs_session_context freshness checks as non-failing while keeping the status visible in MCP freshness output.
• Added a regression for aoa_session_evidence_packet with session-relative raw:line:* refs and no session context.

Why

Codex Review on PR #172 flagged that automatic evidence packets can gather valid session-relative raw refs without a session and should not report freshness.ok=false solely because those refs need session context.

Validation

• Failing-before-fix targeted regression reproduced the freshness.ok=false state.
• git diff --check
• python -m pytest -q mcp/services/aoa-session-memory-mcp/tests/test_session_memory_mcp.py -k 'evidence_packet_combines_trace_search_retrieve_and_freshness or evidence_packet_does_not_fail_session_relative_raw_refs_without_session'
• python mcp/services/aoa-session-memory-mcp/scripts/validate_session_memory_mcp.py
• python -m pytest mcp/services/aoa-session-memory-mcp/tests -q
• python mcp/services/aoa-session-memory-mcp/scripts/release_check.py
• python mcp/services/tos-corpus-mcp/scripts/validate_tos_corpus_mcp.py
• python -m pytest mcp/services/tos-corpus-mcp/tests -q
• python scripts/validate_stack.py
• python scripts/validate_nested_agents.py
• python scripts/ci_gate.py --mode source-fast
• python scripts/release_check.py

Risk

Low: MCP read-only access-plane behavior only; invalid, missing, unknown, or outside-AoA-root refs remain hard freshness failures.

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.