Hide failed-payment order attempts from the customer's own order history

A cancelled order with no invoiceNumber is a Stripe payment that never
succeeded (failed or timed out before ever reaching received/invoiced),
not a real cancellation of something that actually happened — from the
customer's point of view it was never really an order. Filtered out of
getCustomerOrders/getCustomerOrderDetail by default; the row stays in
Payload for admin/audit purposes (shown there as "Zahlung
fehlgeschlagen", see backend).

getCustomerOrderDetail's filter is opt-in via a new optional parameter,
not the default — /api/checkout/status/route.ts's post-payment polling
needs to keep seeing exactly this order to show the "Zahlung
fehlgeschlagen, bitte erneut versuchen" retry state. The GDPR export
route also opts out for the same reason a legal completeness export
can't silently drop rows.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/api/account/export/route.ts

@@ -10,9 +10,9 @@ export async function GET() {
   if (!session) return NextResponse.json({ ok: false, reason: "Bitte zuerst einloggen." }, { status: 401 });
 
   const profile = await getCustomerProfile(session.token);
-  const orderSummaries = await getCustomerOrders(session.token, session.customer.id);
+  const orderSummaries = await getCustomerOrders(session.token, session.customer.id, false);
   const orders = await Promise.all(
-    orderSummaries.map((o) => getCustomerOrderDetail(session.token, session.customer.id, o.orderNumber)),
+    orderSummaries.map((o) => getCustomerOrderDetail(session.token, session.customer.id, o.orderNumber, false)),
   );
 
   const payload = {