fix app.tsx casing on case-insensitive filesystem

src/app.tsx

@@ -0,0 +1,14 @@
+import { RouterProvider, createRouter } from "@tanstack/react-router"
+import { routeTree } from "./routeTree.gen"
+
+const router = createRouter({ routeTree })
+
+declare module "@tanstack/react-router" {
+	interface Register {
+		router: typeof router
+	}
+}
+
+export function App() {
+	return <RouterProvider router={router} />
+}