refactor(invoice): drop dead paid/paidStamp; classify VOIDED; warn on unknown payment status

Audit cleanup of payment-status code paths uncovered while shipping
the partial-refund fix:

#1 Drop `viewModel.paid` (boolean). It was set from
   `displayFinancialStatus === "PAID"` and never read anywhere. With
   refunds in the picture it had become a footgun: a fully refunded
   order that started PAID would still satisfy `paid === true`, but
   `paymentStatus === "refunded"`. Callers should use `paymentStatus`
   / `requiresPayment` exclusively.

#2 Remove the unused `paidStamp` translation ("BEZAHLT" / "PAID").
   Defined in both locales but never rendered.

#3 Classify VOIDED orders as a distinct `"voided"` payment status
   (rendered "Annulliert" / "Voided") instead of "unpaid". A voided
   order had its authorisation cancelled before capture — no money
   was received and none is owed. The previous "Offen" / "Outstanding"
   label combined with a GiroCode would have invited the customer to
   pay an order that's already been called off. `requiresPayment`
   now also excludes `"voided"`, so GiroCode + payment-terms
   paragraph are suppressed (mirrors the `"refunded"` treatment).
   "Annulliert" is used in German rather than "Storniert" to avoid
   confusion with our storno cancellation document concept.

#6 `derivePaymentStatus` now logs a `console.warn` when it
   encounters a non-empty `displayFinancialStatus` value that isn't
   one of the documented Shopify enum members (PAID, PARTIALLY_PAID,
   REFUNDED, PARTIALLY_REFUNDED, VOIDED, PENDING, AUTHORIZED,
   EXPIRED). Future Shopify enum additions will surface in logs
   instead of silently mapping to "unpaid".

EXPIRED stays mapped to "unpaid" — abandoned-checkout-style edge
case left intentionally for a separate decision (#4 in the audit).

Verification: render-sample now also exercises a VOIDED fixture
(status row "Annulliert", no GiroCode, no payment terms). tsc /
smoke / tests / build all green.

scripts/render-sample.ts

@@ -635,6 +635,29 @@ async function main() {
     assert("requiresPayment still false", vmFull.requiresPayment === false);
   }
 
+  // ----------------------------------------------------------------
+  // VOIDED: authorisation cancelled before capture. No money received,
+  // none owed. Must classify as "voided" (not "unpaid") and suppress
+  // GiroCode + payment terms.
+  // ----------------------------------------------------------------
+  console.log("• Voided order (VOIDED) classifies as voided, no GiroCode");
+  {
+    const voidedOrder = { ...buildAtB2BOrder(), displayFinancialStatus: "VOIDED" };
+    const voidedVm = composeInvoice({
+      order: voidedOrder, settings: settings as never, invoiceNumber: "RE-1018",
+    });
+    assertEq("paymentStatus=voided for VOIDED", voidedVm.paymentStatus, "voided");
+    assert("requiresPayment=false for voided", voidedVm.requiresPayment === false);
+    voidedVm.issuer.logoDataUrl = vm.issuer.logoDataUrl;
+    const voidedText = await pdfToText(await renderInvoicePdf(voidedVm));
+    assert("Voided PDF shows the 'Annulliert' status row",
+      voidedText.includes("Annulliert"));
+    assert("Voided PDF does NOT show GiroCode caption",
+      !voidedText.includes("GiroCode"));
+    assert("Voided PDF does NOT show DE payment terms",
+      !voidedText.includes("Bitte überweise"));
+  }
+
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