viewer: break tile inspect into separate entrypoint [#49] (#379)

* viewer: break tile inspect into separate entrypoint [#49]

* fix tsc

app/src/MapView.tsx

@@ -0,0 +1,12 @@
+import React from "react";
+import reactDom from "react-dom/client";
+import MapViewComponent from "./MapViewComponent";
+
+const root = document.getElementById("root");
+if (root) {
+  reactDom.createRoot(root).render(
+    <React.StrictMode>
+      <MapViewComponent />
+    </React.StrictMode>
+  );
+}