feat(frontend): wire Vite app to FastAPI parser with NDJSON streaming + Upload page

src/App.tsx

@@ -0,0 +1,47 @@
+import { Route, Routes } from "react-router-dom";
+import { Toaster } from "sonner";
+import { Layout } from "@/components/Layout";
+import { Dashboard } from "@/pages/Dashboard";
+import { Claims } from "@/pages/Claims";
+import { Remittances } from "@/pages/Remittances";
+import { Providers } from "@/pages/Providers";
+import { ActivityLog } from "@/pages/ActivityLog";
+import { Upload } from "@/pages/Upload";
+
+function NotFound() {
+  return (
+    <div className="min-h-[60vh] flex flex-col items-center justify-center text-center">
+      <div className="display text-[80px] text-muted-foreground/40">404</div>
+      <p className="text-muted-foreground">That page doesn't exist.</p>
+    </div>
+  );
+}
+
+export default function App() {
+  return (
+    <>
+      <Routes>
+        <Route element={<Layout />}>
+          <Route index element={<Dashboard />} />
+          <Route path="claims" element={<Claims />} />
+          <Route path="remittances" element={<Remittances />} />
+          <Route path="providers" element={<Providers />} />
+          <Route path="activity" element={<ActivityLog />} />
+          <Route path="upload" element={<Upload />} />
+          <Route path="*" element={<NotFound />} />
+        </Route>
+      </Routes>
+      <Toaster
+        position="bottom-right"
+        theme="dark"
+        toastOptions={{
+          style: {
+            background: "hsl(var(--card))",
+            border: "1px solid hsl(var(--border))",
+            color: "hsl(var(--foreground))",
+          },
+        }}
+      />
+    </>
+  );
+}