Make public invoices RTL for Farsi businesses and fix invoice back-arrow direction.

Also add optional English name fields on the add-customer modal to match the API.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/business/src/components/InvoiceForm.module.css

@@ -192,6 +192,10 @@
   text-decoration: underline;
 }
 
+:global([dir='rtl']) .backLink svg {
+  transform: scaleX(-1);
+}
+
 .section {
   padding: 16px;
   background: var(--glass-bg);