Blog categories (hasMany), shipping-address contact fields, product SKU on invoices

- Posts.categories is now hasMany — blog list/detail/live-preview render
  a comma-joined list instead of a single category.
- Checkout's "Abweichende Lieferadresse" gains optional Firma + Kontakt-
  E-Mail/Telefon fields (handed to the shipping carrier, not used for
  customer communication).
- Customer profile can now store its own shipping address (mirroring
  Customers.ts's new "Lieferadresse" tab), prefilling the checkout
  override instead of always starting blank.
- Product-level optional SKU (previously only on variants) snapshots onto
  each order item and shows up on invoices (visual + EN16931 XML),
  the confirmation email, and the account order detail page.

app/lib/customerAuth.ts

@@ -203,6 +203,23 @@ export type CustomerAddress = {
   // /checkout's Firma/USt-IdNr. fields for a returning customer.
   companyName: string | null;
   vatId: string | null;
+  // Optional second/shipping address — see Customers.ts's "Lieferadresse"
+  // tab. Prefills /checkout's "Abweichende Lieferadresse" section once
+  // hasDifferentShippingAddress is set here; still fully overwritable per
+  // order (Orders keeps its own shipping* snapshot regardless).
+  hasDifferentShippingAddress: boolean;
+  shippingFirstName: string | null;
+  shippingLastName: string | null;
+  shippingCompanyName: string | null;
+  shippingDeliveryMethod: "address" | "packstation" | null;
+  shippingStreet: string | null;
+  shippingPackstationNumber: string | null;
+  shippingPostNumber: string | null;
+  shippingZip: string | null;
+  shippingCity: string | null;
+  shippingCountry: string | null;
+  shippingContactEmail: string | null;
+  shippingContactPhone: string | null;
 };
 
 export type CustomerProfile = CustomerSummary & CustomerAddress;
@@ -223,6 +240,19 @@ type PayloadCustomerMe = {
   country: string | null;
   companyName: string | null;
   vatId: string | null;
+  hasDifferentShippingAddress: boolean | null;
+  shippingFirstName: string | null;
+  shippingLastName: string | null;
+  shippingCompanyName: string | null;
+  shippingDeliveryMethod: "address" | "packstation" | null;
+  shippingStreet: string | null;
+  shippingPackstationNumber: string | null;
+  shippingPostNumber: string | null;
+  shippingZip: string | null;
+  shippingCity: string | null;
+  shippingCountry: string | null;
+  shippingContactEmail: string | null;
+  shippingContactPhone: string | null;
   cart: { product: number; productSlug: string; quantity: number; variantName: string | null }[] | null;
 };
 
@@ -251,6 +281,19 @@ export async function getCustomerProfile(token: string): Promise<CustomerProfile
     country: u.country,
     companyName: u.companyName,
     vatId: u.vatId,
+    hasDifferentShippingAddress: Boolean(u.hasDifferentShippingAddress),
+    shippingFirstName: u.shippingFirstName,
+    shippingLastName: u.shippingLastName,
+    shippingCompanyName: u.shippingCompanyName,
+    shippingDeliveryMethod: u.shippingDeliveryMethod,
+    shippingStreet: u.shippingStreet,
+    shippingPackstationNumber: u.shippingPackstationNumber,
+    shippingPostNumber: u.shippingPostNumber,
+    shippingZip: u.shippingZip,
+    shippingCity: u.shippingCity,
+    shippingCountry: u.shippingCountry,
+    shippingContactEmail: u.shippingContactEmail,
+    shippingContactPhone: u.shippingContactPhone,
   };
 }
 
@@ -269,6 +312,19 @@ export async function updateCustomerProfile(
     country: string;
     companyName?: string;
     vatId?: string;
+    hasDifferentShippingAddress?: boolean;
+    shippingFirstName?: string;
+    shippingLastName?: string;
+    shippingCompanyName?: string;
+    shippingDeliveryMethod?: "address" | "packstation";
+    shippingStreet?: string;
+    shippingPackstationNumber?: string;
+    shippingPostNumber?: string;
+    shippingZip?: string;
+    shippingCity?: string;
+    shippingCountry?: string;
+    shippingContactEmail?: string;
+    shippingContactPhone?: string;
   },
 ): Promise<{ ok: true } | { ok: false; reason: string }> {
   const res = await fetch(`${PAYLOAD_URL}/api/customers/${customerId}`, {
@@ -495,6 +551,7 @@ export type CustomerOrderDetail = CustomerOrder & {
   hasDifferentShippingAddress: boolean;
   shippingFirstName: string | null;
   shippingLastName: string | null;
+  shippingCompanyName: string | null;
   shippingDeliveryMethod: "address" | "packstation" | null;
   shippingStreet: string | null;
   shippingPackstationNumber: string | null;
@@ -502,6 +559,8 @@ export type CustomerOrderDetail = CustomerOrder & {
   shippingZip: string | null;
   shippingCity: string | null;
   shippingCountry: string | null;
+  shippingContactEmail: string | null;
+  shippingContactPhone: string | null;
   subtotal: number;
   shippingCost: number;
   shippingMethodTitle: string;
@@ -521,6 +580,7 @@ export type CustomerOrderItem = {
   bundleContents: string | null;
   variantName: string | null;
   returnQuantity: number;
+  sku: string | null;
 };
 
 // Access control (Orders.ts) already scopes a customer's own JWT to only