chore: set up routing with mock pages

src/app.tsx

@@ -1,3 +1,5 @@
+import { Router } from "./router";
+
 export function App() {
-  return <h1 className="text-3xl font-bold underline">hello, world!</h1>;
+  return <Router />;
 }

src/pages/episode.tsx

@@ -0,0 +1,3 @@
+export function Episode() {
+  return <h1>Episode page</h1>;
+}

src/pages/home.tsx

@@ -0,0 +1,3 @@
+export function Home() {
+  return <h1>Home page</h1>;
+}

src/pages/podcast.tsx

@@ -0,0 +1,3 @@
+export function Podcast() {
+  return <h1>Podcast page</h1>;
+}

src/router.tsx

@@ -0,0 +1,23 @@
+import { createBrowserRouter, RouterProvider } from "react-router-dom";
+import { Home } from "./pages/home";
+import { Podcast } from "./pages/podcast";
+import { Episode } from "./pages/episode";
+
+const router = createBrowserRouter([
+  {
+    path: "/",
+    element: <Home />,
+  },
+  {
+    path: "/podcast/:podcastId",
+    element: <Podcast />,
+  },
+  {
+    path: "/podcast/:podcastId/episode/:episodeId",
+    element: <Episode />,
+  },
+]);
+
+export function Router() {
+  return <RouterProvider router={router} />;
+}