feat(crm): country dropdown + name guard for customer create/edit

Replace the free-text 2-char country code field on the inline customer
create form and the customer detail page with a dropdown that shows
localized country names (Intl.DisplayNames, no hardcoded map) while
still storing the ISO 3166-1 alpha-2 code. The create form now seeds the
default country from the business profile instead of leaving it blank or
guessing CH/FL. The free-text countryName override is kept for the rare
case where an operator wants a custom display string.

Standardize Liechtenstein on the ISO code LI instead of the colloquial
plate code FL so it matches the PDF renderer's locale-aware lookup and
the new dropdown. Migration 110 normalizes existing FL rows to LI on
customer_accounts and business_profile (idempotent, case-insensitive).

Require at least one human-readable identifier (company name or a
contact name) at create time so the form can't produce a nameless row
that's impossible to recognise in lists later. Enforced on both the
frontend (isValid + toast) and the backend POST /admin/customers
validator so the API can't be bypassed.

i18n: en + de updated; other locales fall back to inline English
defaults and should get a native review before release.

backend/migrations/core/110_normalize_country_code_fl_to_li.js

@@ -0,0 +1,40 @@
+/**
+ * Migration: normalize the Liechtenstein country code from the
+ * colloquial vehicle-plate code `FL` to the ISO 3166-1 alpha-2 code
+ * `LI`.
+ *
+ * Background: the customer create/edit UI used to accept a free-text
+ * 2-char country code and the placeholder suggested `FL` for
+ * Liechtenstein. That code isn't ISO — the PDF renderer's locale-aware
+ * lookup (services/pdfService.js countryName) and the new country
+ * dropdown both key on ISO, so `FL` rows render as the bare code
+ * instead of "Liechtenstein". The dropdown now stores `LI`; this
+ * migration brings existing rows in line so they display correctly and
+ * match new records.
+ *
+ * Scope: customer_accounts.country_code and business_profile.country_code.
+ * Case-insensitive so a hand-entered `fl` is caught too. The free-text
+ * country_name override column is left untouched — it exists precisely
+ * for operators who want a custom display string.
+ *
+ * Idempotent: re-runs only touch rows still holding FL, so a second run
+ * is a no-op.
+ */
+
+async function normalizeColumn(knex, table) {
+  if (!(await knex.schema.hasTable(table))) return;
+  if (!(await knex.schema.hasColumn(table, 'country_code'))) return;
+  await knex(table)
+    .whereRaw('UPPER(country_code) = ?', ['FL'])
+    .update({ country_code: 'LI' });
+}
+
+exports.up = async function(knex) {
+  await normalizeColumn(knex, 'customer_accounts');
+  await normalizeColumn(knex, 'business_profile');
+};
+
+// Irreversible by design: once normalized to the ISO code there's no
+// way to know which `LI` rows were originally `FL`, and reverting would
+// reintroduce the non-ISO value the rest of the system can't read.
+exports.down = async function() {};

backend/src/routes/adminCustomers.js

@@ -245,6 +245,17 @@ router.post('/', [
   body('prefill.country_code').optional({ nullable: true }).isString().isLength({ max: 2 }),
   body('prefill.country_name').optional({ nullable: true }).isString().isLength({ max: 120 }),
   body('prefill.preferred_language').optional({ nullable: true }).isString().isLength({ min: 2, max: 8 }),
+  // At least one human-readable identifier so the record isn't a
+  // nameless row that's impossible to recognise in lists later.
+  body('prefill').custom((prefill) => {
+    const p = prefill || {};
+    const hasName = ['company_name', 'display_name', 'first_name', 'last_name']
+      .some((k) => typeof p[k] === 'string' && p[k].trim());
+    if (!hasName) {
+      throw new Error('At least a company name or a contact name is required');
+    }
+    return true;
+  }),
 ], handleAsync(async (req, res) => {
   validateRequest(req);
   const { id } = await customerAccountsService.createDirect({