生产就绪的身份，
分三行。

'use server'
import { aura } from '@/lib/aurabase'
export async function signIn(formData: FormData) {
  const email = formData.get('email') as string
  const password = formData.get('password') as string
  const { data, error } = await aura.auth.signInWithPassword({
    email, password,
    mfa: 'required',  // enforce TOTP if enrolled
  })
  if (error) return { error: error.message }
  redirect('/dashboard')
}