Route storefront checkout to a local stub outside production

The checkout form and payment-method lookup were hardcoded to the live
payment router, so any local LMS (next dev included) created real
orders: a stray test click on 20261111 produced order 1794380127.

- resolvePayBase(): NEXT_PUBLIC_PAY_BASE_URL if set, otherwise the live
  router for production builds and /dev/pay-stub for everything else.
- /dev/pay-stub/pay/{methods,order}: dev-only stand-ins (404 in
  production) that make no outbound calls and store nothing.
- Document in CLAUDE.md that a local `next build && next start` still
  hits the live router unless NEXT_PUBLIC_PAY_BASE_URL is set.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.env.example

@@ -21,6 +21,12 @@ TURNSTILE_SECRET_KEY=""
 # (ym init snippet) ставится в admin → Settings → headCode, отдельно от этого ID.
 NEXT_PUBLIC_METRIKA_COUNTER_ID=""
 
+# Адрес payment-router для чекаута витрины (/pay/order, /pay/methods). Build-time.
+# Пусто: dev → локальная заглушка /dev/pay-stub, production-сборка → боевой
+# https://obsidian.second-brain.ru. Для локальной `next build && next start`
+# задать явно (например http://localhost:9), иначе форма уйдёт на прод.
+NEXT_PUBLIC_PAY_BASE_URL=""
+
 # Kinescope API
 KINESCOPE_API_KEY=""
 

CLAUDE.md

@@ -220,6 +220,7 @@ S3_REGION="eu-central"
 
 ### Env
 
+- **Чекаут витрины ходит в боевой payment-router из любой production-сборки.** Адрес `/pay/order` и `/pay/methods` выбирает `resolvePayBase` (`src/lib/pay-base.ts`): `NEXT_PUBLIC_PAY_BASE_URL`, иначе при `NODE_ENV=production` — `https://obsidian.second-brain.ru`, иначе — локальная заглушка `/dev/pay-stub` (в проде 404, ничего не сохраняет и не шлёт). `next dev` безопасен, а **локальная `next build && next start` без `NEXT_PUBLIC_PAY_BASE_URL` отправит форму на прод**: реальный заказ, pending в леджере, Telegram владельцу (случай 20261111, заказ 1794380127). Для такой сборки задавать переменную явно, например `http://localhost:9`. Браузерные проверки — только с сетевой блокировкой внешних доменов и без отправки форм.
 - `NEXT_PUBLIC_*` инлайнятся **на сборке**. `NEXT_PUBLIC_APP_URL` задан только как runtime-env в `docker-compose.prod.yml`, в образ не попадает → работает захардкоженный фолбэк на прод-адрес. Следствие: на staging студенту выдаются Zotero-скрипт и curl-пример с **прод**-адресом. Правишь — передавай через `--build-arg`, как `NEXT_PUBLIC_TURNSTILE_SITE_KEY`.
 
 ### Тариф — это отдельный курс со своей копией уроков

src/app/dev/pay-stub/pay/methods/route.ts

@@ -0,0 +1,15 @@
+import { NextResponse } from "next/server";
+
+// Local stand-in for payment-router GET /pay/methods (see src/lib/pay-base.ts).
+// Production: 404. No outbound calls.
+export function GET() {
+  if (process.env.NODE_ENV === "production") {
+    return new NextResponse(null, { status: 404 });
+  }
+  return NextResponse.json({
+    methods: [
+      { id: "stub-card", label: "Заглушка: карта", provider: "dev-stub", kind: "online" },
+      { id: "stub-invoice", label: "Заглушка: счёт", provider: "dev-stub", kind: "manual" },
+    ],
+  });
+}

src/app/dev/pay-stub/pay/order/route.ts

@@ -0,0 +1,28 @@
+import { NextRequest, NextResponse } from "next/server";
+
+// Local stand-in for payment-router POST /pay/order (see src/lib/pay-base.ts).
+// Echoes the submitted fields back as a page. Stores nothing, sends nothing.
+// Production: 404.
+
+function escapeHtml(s: string) {
+  return s.replace(/[&<>"']/g, (c) =>
+    ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" })[c] as string,
+  );
+}
+
+export async function POST(request: NextRequest) {
+  if (process.env.NODE_ENV === "production") {
+    return new NextResponse(null, { status: 404 });
+  }
+  const form = await request.formData();
+  const rows = [...form.entries()]
+    .map(([k, v]) => `<tr><td>${escapeHtml(k)}</td><td>${escapeHtml(typeof v === "string" ? v : "[файл]")}</td></tr>`)
+    .join("");
+  const html = `<!doctype html><meta charset="utf-8"><title>Заглушка оплаты</title>
+<body style="font-family:'Fira Mono',ui-monospace,monospace;background:#F5F5F0;color:#323232;padding:24px">
+<h1 style="font-size:20px">Заглушка оплаты (dev)</h1>
+<p>Заказ не создан, данные никуда не отправлены. Так выглядела бы отправка на payment-router:</p>
+<table style="border:2px solid #323232;border-collapse:collapse" cellpadding="6">${rows}</table>
+<p><a href="/dashboard">← На дашборд</a></p></body>`;
+  return new NextResponse(html, { headers: { "Content-Type": "text/html; charset=utf-8" } });
+}

src/lib/__tests__/pay-base.test.ts

@@ -0,0 +1,20 @@
+import { describe, it, expect } from "vitest";
+import { DEV_PAY_STUB_BASE, LIVE_PAY_BASE, resolvePayBase } from "../pay-base";
+
+describe("resolvePayBase", () => {
+  it("dev без переменной — локальная заглушка", () => {
+    expect(resolvePayBase({ nodeEnv: "development" })).toBe(DEV_PAY_STUB_BASE);
+    expect(resolvePayBase({ nodeEnv: "test" })).toBe(DEV_PAY_STUB_BASE);
+    expect(resolvePayBase({})).toBe(DEV_PAY_STUB_BASE);
+  });
+
+  it("production без переменной — боевой роутер", () => {
+    expect(resolvePayBase({ nodeEnv: "production" })).toBe(LIVE_PAY_BASE);
+    expect(resolvePayBase({ nodeEnv: "production", payBaseUrl: "  " })).toBe(LIVE_PAY_BASE);
+  });
+
+  it("явная переменная побеждает в любом режиме", () => {
+    expect(resolvePayBase({ nodeEnv: "production", payBaseUrl: "http://localhost:9" })).toBe("http://localhost:9");
+    expect(resolvePayBase({ nodeEnv: "development", payBaseUrl: "https://pay.example/" })).toBe("https://pay.example");
+  });
+});

src/lib/pay-base.ts

@@ -0,0 +1,16 @@
+// Where the storefront checkout talks to: the payment router's /pay/order and
+// /pay/methods. Production builds default to the live router; everything else
+// (next dev, tests) defaults to the local stub so a stray click can't create a
+// real order. An explicit NEXT_PUBLIC_PAY_BASE_URL always wins.
+//
+// ⚠️ NODE_ENV is "production" for a local `next build && next start` too —
+// such a build hits the live router unless NEXT_PUBLIC_PAY_BASE_URL is set.
+
+export const LIVE_PAY_BASE = "https://obsidian.second-brain.ru";
+export const DEV_PAY_STUB_BASE = "/dev/pay-stub";
+
+export function resolvePayBase(env: { payBaseUrl?: string; nodeEnv?: string }): string {
+  const explicit = env.payBaseUrl?.trim();
+  if (explicit) return explicit.replace(/\/+$/, "");
+  return env.nodeEnv === "production" ? LIVE_PAY_BASE : DEV_PAY_STUB_BASE;
+}

src/lib/store-catalog.ts

@@ -5,6 +5,8 @@
 // price here is a display bug, not a money bug. When a price changes:
 // products.yaml → landing → this file.
 
+import { resolvePayBase } from "@/lib/pay-base";
+
 export interface StoreTariff {
   sku: string; // must match payment-router/products.yaml
   label: string;
@@ -17,8 +19,13 @@ export interface StoreCatalogEntry {
   tariffs: StoreTariff[];
 }
 
-export const PAY_ORDER_URL = "https://obsidian.second-brain.ru/pay/order";
-export const PAY_METHODS_URL = "https://obsidian.second-brain.ru/pay/methods";
+// Literal process.env.* reads so Next inlines them into the client bundle.
+const PAY_BASE = resolvePayBase({
+  payBaseUrl: process.env.NEXT_PUBLIC_PAY_BASE_URL,
+  nodeEnv: process.env.NODE_ENV,
+});
+export const PAY_ORDER_URL = `${PAY_BASE}/pay/order`;
+export const PAY_METHODS_URL = `${PAY_BASE}/pay/methods`;
 
 // Keys = course slugs shown as locked cards on the student dashboard.
 // Only tariffs of the course's "native" landing are listed — cross-bundles