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>

components/esp-web-install.tsx

@@ -0,0 +1,48 @@
+"use client";
+
+import { createElement, useEffect } from "react";
+
+/**
+ * Loads esp-web-tools once; hosts the install button via slot.
+ */
+export function EspWebInstall({
+  manifest,
+  label,
+  disabled,
+}: {
+  manifest: string | null;
+  label: string;
+  disabled?: boolean;
+}) {
+  useEffect(() => {
+    if (document.querySelector('script[data-esp-web-tools="1"]')) return;
+
+    const script = document.createElement("script");
+    script.type = "module";
+    script.src =
+      "https://unpkg.com/esp-web-tools@10.1.0/dist/web/install-button.js?module";
+    script.dataset.espWebTools = "1";
+    document.head.appendChild(script);
+  }, []);
+
+  const activate = createElement(
+    "button",
+    {
+      slot: "activate",
+      type: "button",
+      className: "cta-btn",
+      disabled: Boolean(disabled || !manifest),
+    },
+    label
+  );
+
+  if (!manifest) {
+    return activate;
+  }
+
+  return createElement(
+    "esp-web-install-button",
+    { manifest },
+    activate
+  );
+}