feat: add typescript monorepo with pnpm workspaces and prisma database package

- root package.json + pnpm-workspace.yaml + tsconfig.base.json
- packages/types: canonical enums (TenantStatus, AgentState)
- packages/shared: re-exports types, base for future utilities
- packages/database: Prisma 7 schema with driver adapter (pg), initial
  tenants table matching agente.md section 29, first migration applied

packages/database/prisma/schema.prisma

@@ -0,0 +1,36 @@
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "postgresql"
+}
+
+enum TenantStatus {
+  TRIAL
+  ACTIVE
+  SUSPENDED
+  PAST_DUE
+  CANCELLED
+
+  @@map("tenant_status")
+}
+
+model Tenant {
+  id               String       @id @default(uuid()) @db.Uuid
+  code             String       @unique
+  slug             String       @unique
+  legalName        String       @map("legal_name")
+  tradeName        String?      @map("trade_name")
+  taxId            String?      @map("tax_id")
+  status           TenantStatus @default(TRIAL)
+  timezone         String       @default("America/Sao_Paulo")
+  locale           String       @default("pt-BR")
+  billingCurrency  String       @map("billing_currency") @default("BRL")
+  telephonyDomain  String?      @map("telephony_domain")
+  createdAt        DateTime     @default(now()) @map("created_at")
+  updatedAt        DateTime     @updatedAt @map("updated_at")
+  deletedAt        DateTime?    @map("deleted_at")
+
+  @@map("tenants")
+}