feat(clock-web): add dashboard page for root route

Added missing (app)/+page.svelte that shows:
- Current time display
- Quick links to World Clock, Alarms, Timers, Stopwatch

This fixes the 404 on the root route.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/clock/apps/web/src/routes/(app)/+page.svelte

@@ -0,0 +1,118 @@
+<script lang="ts">
+	import { onMount } from 'svelte';
+	import { goto } from '$app/navigation';
+	import { Clock, Bell, Timer, Hourglass, Globe } from '@manacore/shared-icons';
+	import { authStore } from '$lib/stores/auth.svelte';
+	import { AppLoadingSkeleton } from '$lib/components/skeletons';
+
+	let isLoading = $state(true);
+
+	onMount(async () => {
+		if (!authStore.isAuthenticated) {
+			goto('/login');
+			return;
+		}
+		isLoading = false;
+	});
+
+	const quickLinks = [
+		{
+			href: '/world-clock',
+			icon: Globe,
+			label: 'Weltzeituhr',
+			description: 'Zeitzonen im Blick',
+			color: 'bg-blue-500',
+		},
+		{
+			href: '/alarms',
+			icon: Bell,
+			label: 'Wecker',
+			description: 'Alarme verwalten',
+			color: 'bg-amber-500',
+		},
+		{
+			href: '/timers',
+			icon: Timer,
+			label: 'Timer',
+			description: 'Countdowns starten',
+			color: 'bg-green-500',
+		},
+		{
+			href: '/stopwatch',
+			icon: Hourglass,
+			label: 'Stoppuhr',
+			description: 'Zeit messen',
+			color: 'bg-purple-500',
+		},
+	];
+</script>
+
+<svelte:head>
+	<title>Clock - Dashboard</title>
+</svelte:head>
+
+{#if isLoading}
+	<AppLoadingSkeleton />
+{:else}
+	<div class="dashboard">
+		<header class="mb-8">
+			<h1 class="text-2xl font-bold text-foreground">Clock</h1>
+			<p class="text-muted-foreground text-sm mt-1">Dein Zeit-Management Hub</p>
+		</header>
+
+		<!-- Current Time Display -->
+		<div class="current-time-card mb-8 p-6 rounded-xl bg-card border border-border">
+			<div class="flex items-center gap-4">
+				<div class="p-3 rounded-full bg-primary/10">
+					<Clock size={32} class="text-primary" />
+				</div>
+				<div>
+					<div class="text-4xl font-bold text-foreground tabular-nums">
+						{new Date().toLocaleTimeString('de-DE', {
+							hour: '2-digit',
+							minute: '2-digit',
+							second: '2-digit',
+						})}
+					</div>
+					<div class="text-muted-foreground">
+						{new Date().toLocaleDateString('de-DE', {
+							weekday: 'long',
+							year: 'numeric',
+							month: 'long',
+							day: 'numeric',
+						})}
+					</div>
+				</div>
+			</div>
+		</div>
+
+		<!-- Quick Links Grid -->
+		<div class="grid grid-cols-2 md:grid-cols-4 gap-4">
+			{#each quickLinks as link}
+				<a
+					href={link.href}
+					class="quick-link p-4 rounded-xl bg-card border border-border hover:border-primary/50 transition-all hover:shadow-lg group"
+				>
+					<div class="flex flex-col items-center text-center gap-3">
+						<div
+							class="{link.color} p-3 rounded-full text-white group-hover:scale-110 transition-transform"
+						>
+							<link.icon size={24} />
+						</div>
+						<div>
+							<div class="font-medium text-foreground">{link.label}</div>
+							<div class="text-xs text-muted-foreground">{link.description}</div>
+						</div>
+					</div>
+				</a>
+			{/each}
+		</div>
+	</div>
+{/if}
+
+<style>
+	.dashboard {
+		max-width: 800px;
+		margin: 0 auto;
+	}
+</style>