Codex: add GAIA map workbench review candidate

[mdheller]

Codex task

Read Agentplane MeshRush candidate examples and validator. Add a review candidate for GAIA /map workbench graph-view review.

Scope

The candidate should represent a governed review handoff for GAIA map workbench state, including OSM feature, H3, MeshRush graph-view, Sherlock evidence, governance, and runtime-boundary context.

Required boundaries

• Advisory by default.
• Approval required if runtime, navigation, dispatch, or safety boundaries would be crossed.
• Do not make the candidate executable.
• Do not introduce direct runtime execution.

Acceptance criteria

• Candidate validates under scripts/validate_meshrush_candidate.py.
• Advisory and approval-required semantics are explicit.
• Existing examples still validate.

Validation command

python3 scripts/validate_meshrush_candidate.py examples/meshrush/*.json

Output expected

Open a PR with a short readout:

• candidate path;
• validation result;
• approval-boundary summary.