feat(customer): add bank account details support

shop/app/my-customers/new/page.tsx

@@ -15,6 +15,7 @@ export default function NewCustomerPage() {
   const [saving, setSaving] = useState(false)
   const [form, setForm] = useState({
     company_name: '', vat_id: '', first_name: '', last_name: '', street: '', zip: '', city: '', email: '',
+    bank_iban: '', bank_bic: '', bank_name: '', bank_owner: '',
   })
 
   const handleSave = async () => {
@@ -62,6 +63,10 @@ export default function NewCustomerPage() {
                 { label: 'Straße & Hausnummer', key: 'street', span: true, placeholder: 'Musterstraße 1' },
                 { label: 'PLZ', key: 'zip', span: false, placeholder: '12345' },
                 { label: 'Ort', key: 'city', span: false, placeholder: 'Musterstadt' },
+                { label: 'Kontoinhaber', key: 'bank_owner', span: false, placeholder: 'Max Mustermann' },
+                { label: 'IBAN', key: 'bank_iban', span: false, placeholder: 'DE89370400440532013000' },
+                { label: 'BIC', key: 'bank_bic', span: false, placeholder: 'SOLADE21XXX' },
+                { label: 'Bankname', key: 'bank_name', span: false, placeholder: 'Musterbank' },
               ] as const).map(({ label, key, span, placeholder }) => (
                 <div key={key} className={`space-y-1.5 ${span ? 'md:col-span-2' : ''}`}>
                   <Label className="text-slate-300 text-sm">{label}</Label>