feat(billing): rating engine, fechamento de periodo, dashboard platform (fase 22)

Fecha a orquestracao de Billing (agente.md secao 120-139) sobre o schema/
RatingEngine puro ja existentes: escritores do ledger UsageEvent
(CALL_SECONDS no CDR, ACTIVE_DAY via sweep diario), closeBillingPeriod/
reopenBillingPeriod (fechamento imutavel com audit trail), e os
controllers de price books/rate decks/plan versions/subscriptions/
periods/statements. Corrige 2 bugs reais de RLS achados no teste ponta a
ponta (reopen sem tenant context, subscriptions sem withTenantContext) e
adiciona teste unitario do RatingEngine (17 casos).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EWHKmcVJtstQFErbZ1AanY

apps/api/src/billing/billing.module.ts

@@ -0,0 +1,19 @@
+import { Module } from "@nestjs/common";
+import { PriceBooksController } from "./price-books.controller";
+import { RateDecksController } from "./rate-decks.controller";
+import { PlanVersionsController } from "./plan-versions.controller";
+import { SubscriptionsController } from "./subscriptions.controller";
+import { BillingPeriodsController } from "./billing-periods.controller";
+import { BillingStatementsController } from "./billing-statements.controller";
+
+@Module({
+  controllers: [
+    PriceBooksController,
+    RateDecksController,
+    PlanVersionsController,
+    SubscriptionsController,
+    BillingPeriodsController,
+    BillingStatementsController,
+  ],
+})
+export class BillingModule {}