refactor: user payment modal

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

frontend/src/lib/components/payments/UserPaymentModal.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+	import { SvelteDate } from 'svelte/reactivity';
 	import { toast } from 'svelte-sonner';
 	import * as Dialog from '$lib/components/ui/dialog';
 	import { Button } from '$lib/components/ui/button';
@@ -92,8 +93,8 @@
 
 	let isExpiryInPast = $derived(
 		expiryParts !== null && (() => {
-			const expiryDate = new Date(expiryParts.year, expiryParts.month);
-			return expiryDate < new Date();
+			const expiryDate = new SvelteDate(expiryParts.year, expiryParts.month);
+			return expiryDate < new SvelteDate();
 		})()
 	);