build: force-include node-mailjet in standalone output

next.config.mjs

@@ -5,6 +5,11 @@ const withNextIntl = createNextIntlPlugin('./src/i18n/request.ts');
 /** @type {import('next').NextConfig} */
 const nextConfig = {
   output: 'standalone',
+  // node-mailjet uses dynamic requires that Next's static tracer misses, so
+  // it never lands in .next/standalone/node_modules. Force-include it.
+  outputFileTracingIncludes: {
+    '**': ['./node_modules/node-mailjet/**/*'],
+  },
   experimental: {
     serverActions: {
       bodySizeLimit: '2mb',