Rename invoice-settings to company-settings, add its own Live Preview, and refine invoice PDF layout

Company data now has its own Payload admin group and a live in-browser
PDF preview (react-pdf's PDFViewer) instead of just a plain settings
form. Invoice header is a brand-colored rule instead of a filled band,
and the footer is now pinned to the page bottom instead of following
content flow.

app/lib/invoicePdf.tsx

@@ -14,7 +14,6 @@ import { formatDate } from "./format";
 // (src/lib/correctionInvoicePdf.tsx in the backend repo, kept visually in
 // sync with this file by eye — not shared code, two separate deployments).
 const BRAND = "#f6a701";
-const BRAND_TINT = "#fdf1d9";
 const TEXT_MUTED = "#6b6b69";
 const BORDER = "#e5e0d8";
 const BG_MUTED = "#f8f5f1";
@@ -23,10 +22,21 @@ const SUCCESS_TINT = "#e7f5eb";
 
 const styles = StyleSheet.create({
   page: { padding: 0, fontSize: 10, fontFamily: "Helvetica", color: "#1a1a18" },
-  headerBand: { backgroundColor: BRAND_TINT, padding: 32, flexDirection: "row", justifyContent: "space-between", alignItems: "center" },
+  // A rule, not a filled band — a bold brand-colored line with a thin
+  // muted second line underneath, rather than a plain 1pt gray divider.
+  headerBand: {
+    padding: 32,
+    paddingBottom: 24,
+    flexDirection: "row",
+    justifyContent: "space-between",
+    alignItems: "center",
+    borderBottomWidth: 3,
+    borderBottomColor: BRAND,
+  },
+  headerRuleThin: { height: 1, backgroundColor: BORDER, marginHorizontal: 32 },
   wordmark: { fontFamily: "Helvetica-Bold", fontSize: 14 },
   kindLabel: { fontFamily: "Helvetica-Bold", fontSize: 22, color: BRAND, letterSpacing: 1 },
-  body: { padding: 32 },
+  body: { padding: 32, paddingBottom: 90 },
   addressRow: { flexDirection: "row", justifyContent: "space-between", marginBottom: 24 },
   addressBlock: { width: "45%" },
   addressLabel: { fontSize: 8, color: TEXT_MUTED, marginBottom: 4, textTransform: "uppercase" },
@@ -55,7 +65,20 @@ const styles = StyleSheet.create({
   grandTotalRow: { flexDirection: "row", justifyContent: "space-between", paddingTop: 8, marginTop: 6, borderTopWidth: 1, borderTopColor: BORDER },
   grandTotalLabel: { fontSize: 12, fontFamily: "Helvetica-Bold" },
   grandTotalValue: { fontSize: 12, fontFamily: "Helvetica-Bold" },
-  footer: { borderTopWidth: 1, borderTopColor: BORDER, paddingTop: 12, fontSize: 8, color: TEXT_MUTED },
+  // `fixed` (below, on the element) + absolute positioning — always pinned
+  // to the bottom of the page regardless of how much content is above it,
+  // rather than just following wherever the content flow happens to end.
+  footer: {
+    position: "absolute",
+    bottom: 32,
+    left: 32,
+    right: 32,
+    borderTopWidth: 1,
+    borderTopColor: BORDER,
+    paddingTop: 12,
+    fontSize: 8,
+    color: TEXT_MUTED,
+  },
 });
 
 function formatPrice(amount: number): string {
@@ -98,6 +121,32 @@ export type InvoiceSeller = {
   bankDetails?: string | null;
 };
 
+// Used only by /company-settings-preview's Live Preview — a fixed sample
+// order so the admin sees a realistic-looking invoice while editing
+// company-settings fields, without depending on any real order existing.
+export const SAMPLE_INVOICE_ORDER: InvoiceOrder = {
+  orderNumber: "#EP-0001-A7K2",
+  invoiceNumber: "RE-0001",
+  invoiceIssuedAt: new Date().toISOString(),
+  customerFirstName: "Max",
+  customerLastName: "Mustermann",
+  deliveryMethod: "address",
+  street: "Musterweg 5",
+  zip: "10115",
+  city: "Berlin",
+  country: "Deutschland",
+  paymentMethodTitle: "Kreditkarte",
+  items: [
+    { productName: "ToDo-Karten – Set", quantity: 1, unitPrice: 12.9, taxRatePercent: 19, bundleContents: null },
+    { productName: "Wochenplaner – Überblick", quantity: 2, unitPrice: 14.9, taxRatePercent: 19, bundleContents: null },
+  ],
+  subtotal: 42.7,
+  shippingCost: 0,
+  discountAmount: 5,
+  discountCode: "WILLKOMMEN10",
+  total: 37.7,
+};
+
 // "Überweisung" (bank transfer) is the only payment method on this shop
 // that ISN'T settled immediately — Kreditkarte/PayPal both capture at
 // checkout. Rather than hardcode a list of "immediate" method titles
@@ -131,7 +180,13 @@ function groupByTaxRate(order: InvoiceOrder, defaultRate: number): { rate: numbe
     .sort((a, b) => b.rate - a.rate);
 }
 
-function InvoiceDocument({ order, seller }: { order: InvoiceOrder; seller: InvoiceSeller }) {
+// Exported (not just used internally by renderInvoicePdf below) so
+// /company-settings-preview's client component can mount it directly with
+// @react-pdf/renderer's browser-side <PDFViewer> — a live, in-browser
+// rendered PDF that re-renders as the admin edits company-settings fields
+// via Payload's postMessage-based useLivePreview(), no server round-trip
+// needed for each keystroke the way an HTML preview would.
+export function InvoiceDocument({ order, seller }: { order: InvoiceOrder; seller: InvoiceSeller }) {
   const rateGroups = groupByTaxRate(order, seller.taxRatePercent);
   const paid = isPaidImmediately(order.paymentMethodTitle);
   const deliveryLine =
@@ -244,13 +299,14 @@ function InvoiceDocument({ order, seller }: { order: InvoiceOrder; seller: Invoi
             </View>
           </View>
 
-          <View style={styles.footer}>
-            <Text>
-              {seller.sellerName} · {seller.sellerStreet}, {seller.sellerZip} {seller.sellerCity} · {seller.sellerEmail} · USt-IdNr.{" "}
-              {seller.vatId}
-            </Text>
-            {seller.bankDetails ? <Text style={{ marginTop: 4 }}>Bankverbindung (für Überweisung): {seller.bankDetails}</Text> : null}
-          </View>
+        </View>
+
+        <View style={styles.footer} fixed>
+          <Text>
+            {seller.sellerName} · {seller.sellerStreet}, {seller.sellerZip} {seller.sellerCity} · {seller.sellerEmail} · USt-IdNr.{" "}
+            {seller.vatId}
+          </Text>
+          {seller.bankDetails ? <Text style={{ marginTop: 4 }}>Bankverbindung (für Überweisung): {seller.bankDetails}</Text> : null}
         </View>
       </Page>
     </Document>