Update Next.js configuration and improve Sentry integration

- Added `serverExternalPackages` to the Next.js configuration to exclude Node-only packages from the webpack bundle, enhancing compatibility with React's RSC/client boundary.
- Refactored Sentry initialization and exception capturing to be asynchronous, ensuring proper handling of the Sentry DSN and preventing potential issues during Next.js builds.
- Updated the `Toaster` component import in the layout to improve UI consistency.

apps/webui/src/components/ui/toaster.tsx

@@ -0,0 +1,7 @@
+'use client';
+
+import { Toaster as SonnerToaster } from 'sonner';
+
+export function Toaster() {
+  return <SonnerToaster richColors position="top-right" />;
+}