Add user auth with JWT, switch to bun test

- User table with company_id FK, unique email, role enum
- Register/login routes with bcrypt + JWT token generation
- Auth plugin with authenticate decorator and role guards
- Login uses globally unique email (no company header needed)
- Dev-auth plugin kept as fallback when JWT_SECRET not set
- Switched from vitest to bun:test (vitest had ESM resolution
  issues with zod in Bun's module structure)
- Upgraded to zod 4
- Added Dockerfile.dev and API service to docker-compose
- 8 tests passing (health + auth)

packages/shared/src/schemas/index.ts

@@ -1,2 +1,2 @@
-// @forte/shared Zod schemas
-// Shared validation schemas will be added as each domain is implemented
+export { UserRole, RegisterSchema, LoginSchema } from './auth.schema.js'
+export type { RegisterInput, LoginInput } from './auth.schema.js'