feat: add AirShelf core implementation

core/frontend/src/main.tsx

@@ -0,0 +1,7 @@
+import { createRoot } from "react-dom/client";
+import { App } from "./App";
+import "./styles.css";
+import "./design-restraint.css";
+import "./exact-pages.css";
+
+createRoot(document.getElementById("root")!).render(<App />);