## Problem

I'm trying to set cookies from my Railway backend and redirect to my localhost frontend during development, but cookies are not being saved in the browser.

## Environment

- **Backend**: NestJS + Fastify on Railway (HTTPS)
- **Frontend**: Next.js on localhost:8000 (HTTP)
- **Flow**: Email verification → Railway backend sets cookie → Redirect to localhost

## Current Setup

### Backend (Railway)
```typescript
// Cookie options
{
  path: '/',
  httpOnly: true,
  sameSite: 'none',
  secure: true
}

// CORS config
{
  origin: 'http://localhost:8000',
  credentials: true
}

// After email verification
reply.setCookie('accessToken', token, cookieOptions);
return reply.status(302).redirect('http://localhost:8000/callback/signup');
```

### Issue
When the backend redirects to localhost, the `Set-Cookie` header is sent but the cookie doesn't appear in the browser.

I understand this is a cross-origin issue (Railway domain → localhost domain), but I'm wondering:

1. Is there a Railway-specific configuration I'm missing?
2. Should I use `trust proxy` settings?
3. What's the recommended approach for development with Railway backend + local frontend?

## What I've Tried
- ✅ `sameSite: 'none'` + `secure: true`
- ✅ CORS `credentials: true`
- ✅ Frontend using `credentials: 'include'`
- ❌ Still no cookies in browser after redirect

Any guidance would be appreciated!