Give every email a full legal footer (Anbieterkennzeichnung), not just a company line

Order confirmation, resend-verification, and the internal critical-alert
mail now render name, street, ZIP/city, email, and VAT ID from
company-settings instead of a bare "<sellerName> · <sellerEmail>" line,
so every email this app sends meets business-correspondence footer
requirements rather than just the customer-facing ones.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -641,16 +641,28 @@ mechanism as Posts/LegalPages/Testimonials (`useLivePreview()` from
   option here). Not shared code with the React page — this is plain
   inline-styled HTML built for email-client compatibility (nested
   `<table>`s, no flexbox) — just matched by eye.
-- **Footer company line is configurable, not hardcoded.** `emailShell()`
-  takes a required `companyLine` parameter ("<sellerName> · <sellerEmail>")
-  — `orderEmail.ts` fetches `company-settings` once (`getSellerForInvoice()`)
-  and derives it from there, same admin-editable business data the invoice
-  PDFs already use, rather than a literal `"einfach produktiv ·
-  admin@mk360.de"` string. The Payload-side sends (password-reset, the 4
-  status-change emails, verification) do the same via that repo's
-  `src/lib/sellerInfo.ts`. Live Preview uses `DEFAULT_COMPANY_LINE` (a
-  fallback constant) since there's no real order/tenant context there to
-  fetch against.
+- **Footer carries a full legal Anbieterkennzeichnung, not just a brand
+  line.** `emailShell()` takes a `footerLines: string[]` array built by
+  `buildLegalFooterLines(seller)` — `sellerName`, `sellerStreet`,
+  `sellerZip`/`sellerCity` (+ `sellerCountry` if not Germany), `E-Mail:
+  sellerEmail`, and `USt-IdNr.: vatId` when set — the same admin-editable
+  `company-settings` fields the invoice PDFs already use, rather than a
+  literal `"einfach produktiv · admin@mk360.de"` string. `orderEmail.ts`
+  and `alertAdmin.ts` (both the resend-verification mail and the plain-text
+  critical-alert mail) all fetch `company-settings` once
+  (`getSellerForInvoice()`) and pass the `seller` object straight into the
+  render functions, which call `buildLegalFooterLines()` themselves — one
+  place composes the footer, not each call site. The Payload-side sends
+  (password-reset, the 4 status-change emails, the *initial* verification
+  email) need the equivalent treatment via that repo's own
+  `src/lib/sellerInfo.ts`, not present in this checkout. Live Preview passes
+  `seller: null`, which falls back to `DEFAULT_LEGAL_FOOTER_LINES` (a
+  placeholder Anbieterkennzeichnung) since there's no real order/tenant
+  context there to fetch against. Note `company-settings` currently has no
+  Handelsregister court/number or Geschäftsführer field — fine for a sole
+  proprietorship, but would need adding if the business becomes a
+  registered legal form (GmbH etc.), see that collection's own field list
+  above.
 
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