Migrate to Vite+ unified toolchain (#428)

src-web/lib/fireAndForget.ts

@@ -0,0 +1,16 @@
+import { showErrorToast } from './toast';
+
+/**
+ * Handles a fire-and-forget promise by catching and reporting errors
+ * via console.error and a toast notification.
+ */
+export function fireAndForget(promise: Promise<unknown>) {
+  promise.catch((err: unknown) => {
+    console.error('Unhandled async error:', err);
+    showErrorToast({
+      id: 'async-error',
+      title: 'Unexpected Error',
+      message: err instanceof Error ? err.message : String(err),
+    });
+  });
+}