fix(email): use invoice language so email matches PDF attachment

app/services/invoice/email.server.ts

@@ -67,8 +67,10 @@ export async function sendInvoiceEmail(
   }
   if (!to) return failLog(args, "No recipient email available.", invoice.id);
 
-  // Build email content.
-  const language = pickLanguage(args.customerLocale ?? settings.defaultLanguage);
+  // Build email content. Always use the language the invoice PDF was
+  // rendered in, so the email matches the attachment. Caller can still
+  // override via `customerLocale` if they really want a different language.
+  const language = pickLanguage(args.customerLocale ?? invoice.language ?? settings.defaultLanguage);
   const t = getStrings(language);
   const customer = parseCustomer(invoice.customerJson);
   const totals = parseTotals(invoice.totalsJson);