test(ci): add exporter heading levels and a11y typography smoke; update MAIN_PLAN

proxy.ts

@@ -0,0 +1,32 @@
+import { NextResponse } from 'next/server'
+import type { NextRequest } from 'next/server'
+import { locales, defaultLocale } from '@/lib/i18n/locales'
+
+function hasLocale(pathname: string) {
+  const first = pathname.split('/')[1]
+  return (locales as readonly string[]).includes(first)
+}
+
+export default function proxy(request: NextRequest) {
+  const { pathname } = request.nextUrl
+
+  // Ignore next internals and assets
+  if (
+    pathname.startsWith('/_next') ||
+    pathname.startsWith('/api') ||
+    pathname.includes('.') // static files
+  ) {
+    return
+  }
+
+  // Add default locale if missing
+  if (!hasLocale(pathname)) {
+    const url = request.nextUrl.clone()
+    url.pathname = `/${defaultLocale}${pathname}`
+    return NextResponse.redirect(url)
+  }
+}
+
+export const config = {
+  matcher: ['/((?!_next|.*\..*).*)'],
+}