fix: stabilize pro checkout loading

frontend/components/account/__tests__/paymentShell.test.ts

@@ -0,0 +1,35 @@
+import fs from "node:fs";
+import path from "node:path";
+
+function assert(condition: unknown, message: string) {
+  if (!condition) throw new Error(message);
+}
+
+export function runTests() {
+  const projectRoot = process.cwd();
+  const accountCenterPath = path.join(
+    projectRoot,
+    "components",
+    "account",
+    "AccountCenter.tsx",
+  );
+  const serviceWorkerPath = path.join(projectRoot, "public", "sw.js");
+
+  const accountCenterSource = fs.readFileSync(accountCenterPath, "utf8");
+  const serviceWorkerSource = fs.readFileSync(serviceWorkerPath, "utf8");
+
+  assert(
+    accountCenterSource.includes(
+      'import { UnlockProOverlay } from "@/components/subscription/UnlockProOverlay";',
+    ),
+    "checkout overlay must be in the account bundle, not lazy-loaded after the user clicks pay",
+  );
+  assert(
+    !/const\s+UnlockProOverlay\s*=\s*dynamic\s*\(/.test(accountCenterSource),
+    "checkout overlay must not be dynamically imported; stale deployments can make the lazy chunk fail at pay time",
+  );
+  assert(
+    !/STATIC_ASSETS\s*=\s*\[[^\]]*["']\/_next\//s.test(serviceWorkerSource),
+    "service worker must not cache-first the whole /_next/ tree; stale chunks break checkout after deploys",
+  );
+}