build: add react vite scaffold

src/App.test.tsx

@@ -0,0 +1,21 @@
+import { renderToString } from "react-dom/server";
+import { describe, expect, test } from "vitest";
+import { AppStateView } from "./App";
+
+describe("React app dashboard state view", () => {
+  test("renders loading dashboard state", () => {
+    const html = renderToString(
+      <AppStateView
+        dashboard={{
+          state: "loading",
+          title: "Loading Dashboard",
+          subtitle: "Fetching active model",
+          message: "Waiting for the active dashboard document.",
+        }}
+      />,
+    );
+
+    expect(html).toContain("Loading Dashboard");
+    expect(html).toContain("Fetching active model");
+  });
+});