Phase 1: Monorepo scaffold, database, and dev environment

Turborepo monorepo with @forte/shared and @forte/backend workspaces.
Docker Compose dev env with PostgreSQL 16 + Valkey 8.
Fastify server with Pino JSON logging, request ID tracing, and
health endpoint. Drizzle ORM with company + location tables.

Includes:
- Root config (turbo, tsconfig, eslint, prettier)
- @forte/shared: types, schemas, currency/date utils
- @forte/backend: Fastify entry, plugins (database, redis, cors,
  error-handler, dev-auth), health route, Drizzle schema + migration
- Dev auth bypass via X-Dev-Company/Location/User headers
- Vitest integration test with clean DB per test (forte_test)
- Seed script for dev company + location

packages/backend/src/test/helpers.ts

@@ -0,0 +1,29 @@
+import type { FastifyInstance } from 'fastify'
+import { buildApp } from '../main.js'
+import { sql } from 'drizzle-orm'
+
+/**
+ * Build a fresh Fastify app instance for testing.
+ * Each test gets its own app — no shared state.
+ */
+export async function createTestApp(): Promise<FastifyInstance> {
+  const app = await buildApp()
+  await app.ready()
+  return app
+}
+
+/**
+ * Truncate all tables in the test database.
+ * Call this in beforeEach to guarantee a clean slate per test.
+ */
+export async function cleanDb(app: FastifyInstance): Promise<void> {
+  await app.db.execute(sql`
+    DO $$ DECLARE
+      r RECORD;
+    BEGIN
+      FOR r IN (SELECT tablename FROM pg_tables WHERE schemaname = 'public') LOOP
+        EXECUTE 'TRUNCATE TABLE ' || quote_ident(r.tablename) || ' CASCADE';
+      END LOOP;
+    END $$
+  `)
+}