fix: remove railway.app fallback, require NEXT_PUBLIC_BASE_URL

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ralyodio

apps/web/app/api/auth/callback/route.ts

@@ -4,7 +4,7 @@ import { createSession, COOKIE } from '@/lib/auth';
 const CLIENT_ID = process.env.COINPAY_API_KEY!;
 const CLIENT_SECRET = process.env.COINPAY_CLIENT_SECRET!;
 const BASE = 'https://coinpayportal.com';
-const APP_URL = process.env.NEXT_PUBLIC_BASE_URL ?? 'https://c0upons.up.railway.app';
+const APP_URL = process.env.NEXT_PUBLIC_BASE_URL!;
 const REDIRECT_URI = `${APP_URL}/api/auth/callback`;
 
 export async function GET(req: NextRequest) {

apps/web/app/api/auth/coinpay/route.ts

@@ -2,7 +2,7 @@ import { NextRequest, NextResponse } from 'next/server';
 
 const CLIENT_ID = process.env.COINPAY_API_KEY!;
 const BASE = 'https://coinpayportal.com';
-const REDIRECT_URI = `${process.env.NEXT_PUBLIC_BASE_URL ?? 'https://c0upons.up.railway.app'}/api/auth/callback`;
+const REDIRECT_URI = `${process.env.NEXT_PUBLIC_BASE_URL}/api/auth/callback`;
 
 function base64url(buf: ArrayBuffer | Uint8Array): string {
   return Buffer.from(buf as ArrayBuffer).toString('base64url');