initial state: muzick music player + recommendation engine

frontend/src/main.tsx

@@ -0,0 +1,29 @@
+import React from 'react';
+import ReactDOM from 'react-dom/client';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { RouterProvider } from '@tanstack/react-router';
+import { router } from './router';
+import { initTheme } from './lib/theme';
+import './index.css';
+
+// Apply the persisted theme before first paint so the whole app is themed.
+initTheme();
+
+const queryClient = new QueryClient({
+  defaultOptions: {
+    queries: {
+      // Per-query staleTime is tuned later (aggressive for static data). This is
+      // just a sane baseline.
+      staleTime: 30_000,
+      refetchOnWindowFocus: false,
+    },
+  },
+});
+
+ReactDOM.createRoot(document.getElementById('root') as HTMLElement).render(
+  <React.StrictMode>
+    <QueryClientProvider client={queryClient}>
+      <RouterProvider router={router} />
+    </QueryClientProvider>
+  </React.StrictMode>
+);