Allow timestamp placeholders for Paddle sandbox tenant email

tests/ui/purchase/paddle-sandbox-full.test.ts

@@ -6,7 +6,7 @@ const shouldRun = process.env.E2E_PADDLE_SANDBOX === '1';
 const baseUrl = process.env.E2E_BASE_URL ?? 'https://test-y0k0.fotospiel.app';
 const locale = process.env.E2E_LOCALE ?? 'de';
 const checkoutSlug = locale === 'en' ? 'checkout' : 'bestellen';
-const tenantEmail = process.env.E2E_TENANT_EMAIL ?? process.env.E2E_PADDLE_EMAIL ?? null;
+const tenantEmail = buildTenantEmail();
 const tenantPassword = process.env.E2E_TENANT_PASSWORD ?? null;
 const sandboxCard = {
   number: process.env.E2E_PADDLE_CARD_NUMBER ?? '4242 4242 4242 4242',
@@ -178,6 +178,20 @@ async function completeHostedPaddleCheckout(
   await payButton.click();
 }
 
+function buildTenantEmail(): string | null {
+  const rawEmail = process.env.E2E_TENANT_EMAIL ?? process.env.E2E_PADDLE_EMAIL ?? null;
+  if (!rawEmail) {
+    return null;
+  }
+
+  if (!rawEmail.includes('{timestamp}')) {
+    return rawEmail;
+  }
+
+  const timestamp = Math.floor(Date.now() / 1000).toString();
+  return rawEmail.replaceAll('{timestamp}', timestamp);
+}
+
 async function fillInAnyFrame(page: Page, selectors: string[], value: string): Promise<void> {
   const filled = await attemptFill(page, selectors, value);
   if (filled) {