fix(frontend): Svelte 5 reactivity, each block keys, and path resolution

Add proper keys to #each blocks across 15+ components to fix reordering bugs. Replace new Date() with SvelteDate in reactive contexts. Use $derived for computed values (totalPages). Use resolve() from $app/paths for all internal navigation hrefs. Add ARIA labels and keyboard accessibility to NavBar mobile menu. Remove unused handleRetry from UserPaymentModal.

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

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

frontend/src/routes/schedule/+page.svelte

@@ -1,16 +1,18 @@
 <script lang="ts">
 	import { goto } from '$app/navigation';
+	import { resolve } from '$app/paths';
 	import { authStore } from '$lib/stores/auth.svelte';
 	import { browser } from '$app/environment';
 	import { toast } from 'svelte-sonner';
 	import { SvelteDate } from 'svelte/reactivity';
 	import UserBookingModal from '$lib/components/account/UserBookingModal.svelte';
+	import type { Booking, BookingService } from '$lib/types/booking';
 
 	import { Button } from '$lib/components/ui/button';
 	import * as Card from '$lib/components/ui/card';
 
 	let pageState = $state<'loading' | 'authorized' | 'unauthorized'>('loading');
-	let bookings = $state<any[]>([]);
+	let bookings = $state<Booking[]>([]);
 	let loading = $state(false);
 	let selectedBookingId = $state<string | null>(null);
 	let showBookingModal = $state(false);
@@ -53,13 +55,13 @@
 			const now = new SvelteDate();
 
 			bookings = (data.bookings || [])
-				.filter((b: any) => {
+				.filter((b: Booking) => {
 					const startTime = new SvelteDate(b.start_time);
 					const endTime = new SvelteDate(startTime.getTime() + (b.duration_minutes || 0) * 60000);
 					return endTime > now;
 				})
 				.sort(
-					(a: any, b: any) =>
+					(a: Booking, b: Booking) =>
 						new SvelteDate(a.start_time).getTime() - new SvelteDate(b.start_time).getTime()
 				);
 		} catch (err) {
@@ -107,7 +109,7 @@
 					<Card.Description>You don't have any upcoming appointments.</Card.Description>
 				</Card.Header>
 				<Card.Content>
-					<Button href="/book">Book an Appointment</Button>
+					<Button href={resolve('/book')}>Book an Appointment</Button>
 				</Card.Content>
 			</Card.Root>
 		{:else}
@@ -146,7 +148,7 @@
 								<div>
 									{#if booking.services && booking.services.length > 0}
 										<p class="font-medium">
-											{booking.services.map((s: any) => s.service_name).join(', ')}
+											{booking.services.map((s: BookingService) => s.service_name).join(', ')}
 										</p>
 									{/if}
 									{#if booking.total_amount}