Add CYD browser flasher with Next.js, i18n, and Web Serial install.

Replace the starter app with a public/local flasher that discovers sibling firmwares, supports en/zh, and documents HTTPS deploy.

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

app/robots.ts

@@ -0,0 +1,12 @@
+import type { MetadataRoute } from "next";
+
+export default function robots(): MetadataRoute.Robots {
+  const base = process.env.NEXT_PUBLIC_SITE_URL || "http://localhost:3000";
+  return {
+    rules: {
+      userAgent: "*",
+      allow: "/",
+    },
+    sitemap: `${base}/sitemap.xml`,
+  };
+}