- M3.6.2: ObsidianRefSource (fetch + chunk from Obsidian API) - M3.6.4: ReferenceCycleGuard (prevent R re-entry as evidence) - M3.6.5: QueryLevels (multi-tier filtering, R opt-in) - M3.6.6-8: Composition gate + enrichment + deduplication - Tests: 12 assertions validating no system regression