Dynamic AGB address, real shipping costs on /versand instead of hardcoded constants

- AGB: name/address/email now come from company-settings via new
  VertragspartnerBlock (mid-document, see LegalPages.ts's contentPart2).
- VersandSections/VersandModal/CartContent/CheckoutContent/versand page:
  shipping cost and free-shipping threshold now come from the real
  ShippingMethods data (already fetched elsewhere for checkout), not the
  hardcoded lib/shipping.ts constants — those had already drifted from
  the real Payload values once. lib/shipping.ts deleted, nothing left to
  export.

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

app/cart/components/CartContent.tsx

@@ -524,7 +524,13 @@ export function CartContent({
         </Reveal>
       )}
 
-      <VersandModal open={versandOpen} onClose={() => setVersandOpen(false)} shipping={shippingSettings} />
+      <VersandModal
+        open={versandOpen}
+        onClose={() => setVersandOpen(false)}
+        shipping={shippingSettings}
+        shippingCost={shippingCost}
+        freeShippingThreshold={freeShippingThreshold}
+      />
     </>
   );
 }