The gap-fill is wired end-to-end (slices 5a-5e) behind seams; this note is what's
left to switch it on in production: (1) implement the PredictionTargetAttributesReader
stub over property_overrides — with the override-value → API-code mapping
select_comparables needs; (2) run the epc_property.source Drizzle migration; (3)
pass the three optional collaborators at the IngestionOrchestrator composition
root. Plus the open Validation-Cohort exclusion (no code path exists yet — exclude
on source_path == "predicted" when one is built) and the anomaly dual-use pointer.
No code change: the validation exclusion has no consumer to attach to today, and
the structural signal (source_path == "predicted") already exists from slice-5a.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>