9de87d2d51
TDD tasks: schema columns catalog reader, column_promoted/excluded ledger types (+ F4 emits), deterministic sync-schema-linking projection, the reviewer_schema_linking gate tool (+ stringified-tables handling), SKILL.md Phase 4 guidance, backend passthrough test, promoted_columns_for helper, and live end-to-end verification. Hard SQL enforcement documented as a non-goal (fragile through CTEs); curated columns are persisted + honored softly. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>