build: add react vite scaffold

src/App.tsx

@@ -0,0 +1,32 @@
+import type { DashboardRuntimeState } from "$lib/server/dashboard";
+
+export function AppStateView({
+  dashboard,
+}: {
+  dashboard: DashboardRuntimeState;
+}) {
+  if (dashboard.state === "ready") {
+    return <main>{dashboard.document.metadata.title}</main>;
+  }
+
+  return (
+    <main className="state-shell" data-dashboard-state={dashboard.state}>
+      <h1>{dashboard.title}</h1>
+      <p>{dashboard.subtitle}</p>
+      <p>{dashboard.message}</p>
+    </main>
+  );
+}
+
+export default function App() {
+  return (
+    <AppStateView
+      dashboard={{
+        state: "loading",
+        title: "Loading Dashboard",
+        subtitle: "Fetching active model",
+        message: "Waiting for the active dashboard document.",
+      }}
+    />
+  );
+}