fix(invoice): detect pickup via DeliveryMethodType and show 'Abholort: <location>' meta row

- Use Order.fulfillmentOrders.deliveryMethod.methodType === 'PICK_UP' as the
  primary signal (Shopify Local Pickup app exposes this reliably; the
  shippingLine title is just the location name with no 'pickup' keyword).
  Keep the legacy shippingLine string heuristic as a fallback for custom
  shipping rates merchants name 'Abholung'/'Pickup'.
- Surface assignedLocation.name as pickupLocationName on the view model.
- Replace the 'Versandart: <location name>' row with 'Abholort: <location>'
  (DE) / 'Pick-up location: <location>' (EN); falls back to plain
  'Abholung'/'Pick-up' when the location name is unavailable.

app/services/invoice/i18n.ts

@@ -65,6 +65,9 @@ export interface InvoiceStrings {
   shippingItemPrefix: string;
   discountCodeLabel: string;
   pickupLabel: string;
+  /** Used as the meta-row label when the order is a local pickup. The row
+   *  value is then the pickup location name (e.g. "Lager Graz"). */
+  pickupLocationLabel: string;
 }
 
 /** Status displayed for the order's payment, derived from Shopify's
@@ -167,6 +170,7 @@ const de: InvoiceStrings = {
   shippingItemPrefix: "Versand",
   discountCodeLabel: "Rabattcode",
   pickupLabel: "Abholung",
+  pickupLocationLabel: "Abholort",
 };
 
 const en: InvoiceStrings = {
@@ -236,6 +240,7 @@ const en: InvoiceStrings = {
   shippingItemPrefix: "Shipping",
   discountCodeLabel: "Discount code",
   pickupLabel: "Pick-up",
+  pickupLocationLabel: "Pick-up location",
 };
 
 // Locale → invoice language. We only render in German (`de`) when the