feat(hierarchy): audit event + outbox machinery (M4-1b-i, contract 1 §5.2) (#1460)

packages/db/src/schema.ts

@@ -4,6 +4,7 @@
  */
 
 import { sql } from 'drizzle-orm';
+import type { AnyPgColumn } from 'drizzle-orm/pg-core';
 import {
   pgTable,
   pgEnum,
@@ -1152,3 +1153,111 @@ export const hierarchyGrants = pgTable(
     index('hierarchy_grants_granted_by_idx').on(t.grantedBy),
   ],
 );
+
+// ─── Hierarchy audit events + outbox (contract 1 §5.2) ──────────────────────
+// NOT part of the record class (the class is exactly the five tables above).
+// Append-only semantic audit log for hierarchy mutations, with a dedicated
+// transactional outbox — hierarchy events are not workspace-scoped rows and
+// do not ride the workspace outbox. Deletion-safe linkage: events reference
+// their target by an immutable snapshot (id, slug, parent chain at event
+// time), never by a foreign key into the class tables, so append-only events
+// survive the deletion of their target. Append-only is enforced at the
+// application layer (the hierarchy audit repository exposes no update/delete
+// path for events); REQ-AUD-001's INSERT/SELECT-only database role is a
+// deployment concern outside this schema.
+
+export const HIERARCHY_AUDIT_VERBS = [
+  'create',
+  'rename',
+  'transfer',
+  'delete',
+  'grant_create',
+  'grant_change',
+  'grant_revoke',
+] as const;
+
+export const HIERARCHY_AUDIT_TARGET_KINDS = [
+  'company',
+  'estate',
+  'platform_project',
+  'grant',
+] as const;
+
+export const hierarchyAuditEvents = pgTable(
+  'hierarchy_audit_events',
+  {
+    id: uuid('id').primaryKey().defaultRandom(),
+    // Global append order; per-target ordering (REQ-AUD-001) is a filter on
+    // target_id ordered by seq.
+    seq: bigint('seq', { mode: 'number' }).notNull().generatedAlwaysAsIdentity(),
+    // No FK: audit events outlive every principal and every target (§5.2).
+    actorId: text('actor_id').notNull(),
+    verb: text('verb').notNull(),
+    targetKind: text('target_kind').notNull(),
+    targetId: uuid('target_id').notNull(),
+    // Immutable snapshot at event time. Node events: { id, slug, name,
+    // parentChain: [{ kind, id, slug }, …] root-first }. Grant events:
+    // { id, subject: { userId | teamId }, target: { kind, id }, role }
+    // (subject and role per contract 2 §4.4).
+    targetSnapshot: jsonb('target_snapshot').notNull(),
+    // Present exactly on transfers: snapshot of the source/destination
+    // parent ({ kind, id, slug }), CHECK-enforced below.
+    transferFrom: jsonb('transfer_from'),
+    transferTo: jsonb('transfer_to'),
+    correlationId: text('correlation_id').notNull(),
+    // Prior event in the causal chain (e.g. cascaded grant_revoke events
+    // caused by a node delete). Self-FK RESTRICT keeps the chain intact.
+    causationId: uuid('causation_id').references((): AnyPgColumn => hierarchyAuditEvents.id, {
+      onDelete: 'restrict',
+    }),
+    idempotencyKey: text('idempotency_key').notNull(),
+    occurredAt: timestamp('occurred_at', { withTimezone: true }).notNull().defaultNow(),
+  },
+  (t) => [
+    uniqueIndex('hierarchy_audit_events_idempotency_idx').on(t.idempotencyKey),
+    uniqueIndex('hierarchy_audit_events_seq_idx').on(t.seq),
+    index('hierarchy_audit_events_target_seq_idx').on(t.targetId, t.seq),
+    index('hierarchy_audit_events_correlation_idx').on(t.correlationId),
+    check(
+      'hierarchy_audit_events_verb_check',
+      sql`verb IN ('create', 'rename', 'transfer', 'delete', 'grant_create', 'grant_change', 'grant_revoke')`,
+    ),
+    check(
+      'hierarchy_audit_events_target_kind_check',
+      sql`target_kind IN ('company', 'estate', 'platform_project', 'grant')`,
+    ),
+    check(
+      'hierarchy_audit_events_transfer_check',
+      sql`(verb = 'transfer') = (transfer_from IS NOT NULL AND transfer_to IS NOT NULL)`,
+    ),
+  ],
+);
+
+export const hierarchyOutboxStatusEnum = pgEnum('hierarchy_outbox_status', [
+  'pending',
+  'processing',
+  'delivered',
+]);
+
+export const hierarchyOutbox = pgTable(
+  'hierarchy_outbox',
+  {
+    id: uuid('id').primaryKey().defaultRandom(),
+    // FK into the append-only events table (not a class table): never
+    // dangles, so RESTRICT is safe and keeps event/outbox integrity.
+    eventId: uuid('event_id')
+      .notNull()
+      .references(() => hierarchyAuditEvents.id, { onDelete: 'restrict' }),
+    idempotencyKey: text('idempotency_key').notNull(),
+    correlationId: text('correlation_id').notNull(),
+    status: hierarchyOutboxStatusEnum('status').notNull().default('pending'),
+    createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+    updatedAt: timestamp('updated_at', { withTimezone: true }).notNull().defaultNow(),
+    deliveredAt: timestamp('delivered_at', { withTimezone: true }),
+  },
+  (t) => [
+    uniqueIndex('hierarchy_outbox_event_idx').on(t.eventId),
+    uniqueIndex('hierarchy_outbox_idempotency_idx').on(t.idempotencyKey),
+    index('hierarchy_outbox_status_created_idx').on(t.status, t.createdAt),
+  ],
+);