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/plugins/database.ts

@@ -0,0 +1,28 @@
+import fp from 'fastify-plugin'
+import { drizzle } from 'drizzle-orm/postgres-js'
+import postgres from 'postgres'
+import * as schema from '../db/schema/stores.js'
+
+declare module 'fastify' {
+  interface FastifyInstance {
+    db: ReturnType<typeof drizzle<typeof schema>>
+    sql: ReturnType<typeof postgres>
+  }
+}
+
+export const databasePlugin = fp(async (app) => {
+  const connectionString = process.env.DATABASE_URL
+  if (!connectionString) {
+    throw new Error('DATABASE_URL environment variable is required')
+  }
+
+  const sql = postgres(connectionString)
+  const db = drizzle(sql, { schema })
+
+  app.decorate('db', db)
+  app.decorate('sql', sql)
+
+  app.addHook('onClose', async () => {
+    await sql.end()
+  })
+})