add feed in / out button page and also button to redirect to button page

button/index.html

@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Feed In/Out Button</title>
+    <link rel="icon" type="image/png" href="/favicon.png" />
+    <script src="https://cdn.tailwindcss.com?plugins=typography"></script>
+    <link
+      rel="stylesheet"
+      href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css"
+      integrity="sha512-DTOQO9RWCH3ppGqcWaEA1BIZOC6xxalwEsw9c2QQeAIftl+Vegovlnee1c9QX4TctnWMn13TZye+giMm8e2LwA=="
+      crossorigin="anonymous"
+      referrerpolicy="no-referrer"
+    />
+  </head>
+  <body class="bg-gray-100">
+    <div id="root"></div>
+    <script type="module" src="/button/main.tsx"></script>
+  </body>
+</html>

button/main.tsx

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+import React from 'react';
+import ReactDOM from 'react-dom/client';
+import ButtonApp from '../ButtonApp.tsx';
+import ErrorBoundary from '../components/common/ErrorBoundary.tsx';
+
+const rootElement = document.getElementById('root');
+if (!rootElement) {
+  throw new Error('Could not find root element to mount to');
+}
+
+ReactDOM.createRoot(rootElement).render(
+  <React.StrictMode>
+    <ErrorBoundary>
+      <ButtonApp />
+    </ErrorBoundary>
+  </React.StrictMode>
+);