Profile: Rechnungsadresse is always a street address, no Packstation toggle

Matches /checkout's own billing card exactly (an invoice needs a real
postal address) — the profile form previously offered a Lieferart/
Packstation choice for what's actually always used as the billing
address, inconsistent now that a separate "Lieferadresse" section exists.

README.md

@@ -1999,6 +1999,43 @@ field-lock security logic is still tested in the **Payload backend's**
 own `test:unit` — see that repo's README's own "Tests" section, since
 that's where that logic actually lives.
 
+## 2026-07-30 changes
+
+**Blog posts can have multiple categories.** `BlogPost.categories` is now
+`string[]` (was a single `category: string`), joined with `", "` wherever
+a single category used to render (`/blog`, `/blog/[slug]`,
+`LivePostContent.tsx`, `components/Blog.tsx`). Backend field is
+`Posts.categories`, a `hasMany` relationship — see the Payload backend's
+own README.
+
+**Checkout's "Abweichende Lieferadresse" gained Firma + Kontakt-E-Mail/
+Telefon** (all optional) — handed to the shipping carrier, not used for
+any customer communication (that stays the account email above). Backed
+by new `Orders.shipping*` fields with no shipping-side `vatId` (billing-
+only concept, deliberately not mirrored).
+
+**The customer profile (`/konto/profil`) can now store its own shipping
+address**, mirroring the checkout's own "Abweichende Lieferadresse"
+section field-for-field (same checkbox pattern, same fields incl. the new
+Firma/Kontakt fields above) — prefills the checkout section for a
+returning customer instead of always starting blank. Backed by
+`Customers`' new "Lieferadresse" tab in the Payload backend.
+
+**Products can have an optional SKU** even without variants
+(`Products.sku` — variants already had their own). Snapshotted onto each
+order item at checkout (`app/api/checkout/route.ts` — variant SKU takes
+precedence over the product's own) and shown as "Art.-Nr." on the invoice
+PDF, the order-confirmation email, and `/konto/bestellungen/[orderNumber]`.
+
+**`@einfach-produktiv/invoicing` bumped to 0.2.7** for the SKU +
+shipping-contact rendering above — re-run `npm install
+@einfach-produktiv/invoicing` after pulling if your local `node_modules`
+predates this.
+
+Full plan for an n8n-driven blog-post content-automation pipeline (not yet
+built) lives in the Payload backend repo's `docs/blog-automation-plan.md`,
+not duplicated here since it changes independently of this frontend.
+
 ## Deployment
 
 - **Dockerfile**: 3-stage build (`deps` → `builder` → `runner`) with