add Vite-based app for example TypeScript application

app/src/App.tsx

@@ -0,0 +1,36 @@
+import { useState, useEffect } from "react";
+import { styled, globalStyles } from "./stitches.config";
+
+import Start from "./Start";
+import Inspector from "./Inspector";
+import LeafletMap from "./LeafletMap";
+import MaplibreMap from "./MaplibreMap";
+
+const Header = styled("div", {
+  height: "$4",
+});
+
+function App() {
+  globalStyles();
+
+  const existingValue = new URLSearchParams(location.search).get("file") || "";
+
+  let [file, setFile] = useState<string>(existingValue);
+
+  useEffect(() => {
+    if (file) {
+      const url = new URL(window.location.href);
+      url.searchParams.set("file", file);
+      history.pushState(null, "", url.toString());
+    }
+  }, [file]);
+
+  return (
+    <div>
+      <Header>pmtiles viewer | github | toggle</Header>
+      {file ? <MaplibreMap file={file} /> : <Start setFile={setFile} />}
+    </div>
+  );
+}
+
+export default App;