Postgres Schema + Migrations + Workflow Guardrails

Title: Postgres schema + stored procedures for versioned workflow with Signwell approvals
Scope
Implement Postgres 14 schema contract for ops-first deal capture, immutable core.deal_version snapshots, deterministic approval requirements, and Signwell integration scaffolding. Postgres is the system of record. n8n is glue. Retool is the UI, Signwell is the external approval tool. Xero for financial drafts, posting and ingestion.
Deliverables
1) Schemas + tables
Create: raw, ops, core, audit, config, security.
ops (editable workspace)
• ops.deal_draft
• ops.deal_draft_party
• ops.deal_draft_broker
• ops.deal_draft_economics
• ops.deal_draft_doc_status
• ops.validation_result
• ops.exception_queue
• ops.correction_task
core (immutable snapshots + gating)
•
• core.deal_version (major/minor ready; v1 can always create new version)
• core.deal_version_party
• core.deal_version_broker
• core.deal_version_economics
• core.deal_vers...