Audit the project's Flow ecosystem (BF/UF/SF/SM/FR/API IDs across docs/2-contracts/) for consistency violations. Detects broken refs, orphan flows, layering violations, stale flows, and flow-index drift. Triggers on 'audit flows', 'check flow consistency', 'find broken refs', '稽核 flow', 'flow 一致性檢查', 'is flow-index up to date'. Reports only — does not modify files.
