fix(invoice): suppress GiroCode + payment terms for refunded (and paid) orders

User reported that fully refunded orders still rendered a SEPA GiroCode
QR asking the customer to wire the original total. The existing gate
("!viewModel.paid") only excluded literally-PAID orders; REFUNDED,
PARTIALLY_REFUNDED, VOIDED, AUTHORIZED, etc. all sneaked through and
produced a confusing payment request for an order whose outstanding
balance is in fact 0.

Root cause: the view model exposed two related but ambiguous flags
("paid" and "paymentStatus") and the renderer mixed them
inconsistently. Both the GiroCode generation step in
generateInvoice.server.tsx AND the GiroCode/payment-terms render gates
in InvoiceDocument.tsx checked the wrong one.

Fix: introduce a single derived "requiresPayment" flag on the view
model (composeInvoice.ts) that is true only when:
  - the document is a regular invoice (not a storno or an offer), AND
  - paymentStatus is neither "paid" nor "refunded".

That single flag now drives:
  - GiroCode QR generation (skip QR fetch for paid/refunded)
  - GiroCode block render in the PDF
  - payment-terms paragraph render in the PDF

The existing "Zahlstatus: Erstattet" / "Payment status: Refunded"
meta-row continues to communicate the refund visually — the change
just removes the contradictory call-to-pay.

Side benefits:
  - Storno (cancellation invoice) PDFs no longer emit the German
    "Bitte überweise …" payment-terms paragraph (kind=storno was
    falling through the same not-paid branch).
  - Same suppression for fully PAID orders (covered by a second smoke
    fixture) so the QR doesn't suggest re-payment after the fact.

Verification: new smoke fixtures (REFUNDED + PAID) build a real
GiroCode data URL and verify the PDF text neither contains the
"GiroCode" caption nor the "Bitte überweise" German payment terms,
while still showing the corresponding "Erstattet" / "Bezahlt" status
row. tsc / smoke / tests / build all green.

scripts/render-sample.ts

@@ -507,6 +507,61 @@ async function main() {
   assert("storno PDF > 5 KB", stornoBuf.length > 5_000, `actual ${stornoBuf.length}`);
   console.log(`  → wrote ${stornoOut} (${stornoBuf.length} bytes)`);
 
+  // ----------------------------------------------------------------
+  // Refunded order: GiroCode + payment-terms must be suppressed
+  // ----------------------------------------------------------------
+  console.log("• Refunded order (REFUNDED) suppresses GiroCode + payment terms");
+  {
+    const refundedOrder = { ...buildAtB2BOrder(), displayFinancialStatus: "REFUNDED" };
+    const refundedVm = composeInvoice({
+      order: refundedOrder, settings: settings as never, invoiceNumber: "RE-1014",
+    });
+    assertEq("paymentStatus=refunded", refundedVm.paymentStatus, "refunded");
+    assert("requiresPayment=false for refunded", refundedVm.requiresPayment === false);
+    refundedVm.issuer.logoDataUrl = vm.issuer.logoDataUrl;
+    // The orchestrator gates GiroCode generation on requiresPayment too —
+    // simulate that here by NOT attaching giroCodePngDataUrl. The PDF
+    // render-gate must independently refuse to render even if a stale
+    // QR data URL were attached, so set one anyway and verify both
+    // suppression layers.
+    refundedVm.giroCodePngDataUrl = await buildGiroCodeDataUrl({
+      beneficiaryName: settings.companyName,
+      iban: settings.iban,
+      bic: settings.bic,
+      amount: refundedVm.totals.gross,
+      remittance: refundedVm.number,
+    });
+    const refundedText = await pdfToText(await renderInvoicePdf(refundedVm));
+    assert("Refunded PDF does NOT show GiroCode caption",
+      !refundedText.includes("GiroCode"));
+    assert("Refunded PDF does NOT show DE payment terms",
+      !refundedText.includes("Bitte überweise"));
+    assert("Refunded PDF still shows the 'Erstattet' status row",
+      refundedText.includes("Erstattet"));
+  }
+
+  // Same gating must apply to PAID orders.
+  console.log("• Paid order (PAID) suppresses GiroCode + payment terms");
+  {
+    const paidOrder = { ...buildAtB2BOrder(), displayFinancialStatus: "PAID" };
+    const paidVm = composeInvoice({
+      order: paidOrder, settings: settings as never, invoiceNumber: "RE-1015",
+    });
+    assert("requiresPayment=false for paid", paidVm.requiresPayment === false);
+    paidVm.issuer.logoDataUrl = vm.issuer.logoDataUrl;
+    paidVm.giroCodePngDataUrl = await buildGiroCodeDataUrl({
+      beneficiaryName: settings.companyName,
+      iban: settings.iban,
+      bic: settings.bic,
+      amount: paidVm.totals.gross,
+      remittance: paidVm.number,
+    });
+    const paidText = await pdfToText(await renderInvoicePdf(paidVm));
+    assert("Paid PDF does NOT show GiroCode caption", !paidText.includes("GiroCode"));
+    assert("Paid PDF does NOT show DE payment terms", !paidText.includes("Bitte überweise"));
+    assert("Paid PDF shows the 'Bezahlt' status row", paidText.includes("Bezahlt"));
+  }
+
   // ----------------------------------------------------------------
   // Footer note translation
   // ----------------------------------------------------------------