feat(ui): build app shell with chapters, editor and preview dock

src/main.tsx

@@ -0,0 +1,12 @@
+import React from "react";
+import ReactDOM from "react-dom/client";
+import App from "./App";
+import "./styles/fonts.css";
+import "./styles/tokens.css";
+import "./styles/app.css";
+
+ReactDOM.createRoot(document.getElementById("root") as HTMLElement).render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>
+);