Add SvelteKit frontend with Tailwind CSS (Phase 4)

Build a modern, calm web UI using SvelteKit 5 + Tailwind CSS v4.

Pages:
- Setup wizard (first-run admin account creation)
- Login with JWT token management and auto-refresh
- Dashboard with stats cards and recent events timeline
- Servers: add/delete Immich server connections with validation
- Trackers: create album trackers with album picker, event type
  selection, target assignment, and scan interval config
- Templates: Jinja2 message template editor with live preview
- Targets: Telegram and webhook notification targets with test
- Users: admin-only user management (create/delete)

Architecture:
- Reactive auth state with Svelte 5 runes
- API client with JWT auth, auto-refresh on 401
- Static adapter builds to 153KB for embedding in FastAPI
- Vite proxy config for dev server -> backend API
- Sidebar layout with navigation and user info

Also adds Rule 2 to primary plan: perform detailed code review
after completing each phase.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/routes/+page.svelte

@@ -0,0 +1,56 @@
+<script lang="ts">
+	import { onMount } from 'svelte';
+	import { api } from '$lib/api';
+	import PageHeader from '$lib/components/PageHeader.svelte';
+	import Card from '$lib/components/Card.svelte';
+
+	let status = $state<any>(null);
+
+	onMount(async () => {
+		try { status = await api('/status'); } catch { /* ignore */ }
+	});
+</script>
+
+<PageHeader title="Dashboard" description="Overview of your Immich Watcher setup" />
+
+{#if status}
+	<div class="grid grid-cols-1 sm:grid-cols-3 gap-4 mb-8">
+		<Card>
+			<p class="text-sm text-[var(--color-muted-foreground)]">Servers</p>
+			<p class="text-3xl font-semibold mt-1">{status.servers}</p>
+		</Card>
+		<Card>
+			<p class="text-sm text-[var(--color-muted-foreground)]">Active Trackers</p>
+			<p class="text-3xl font-semibold mt-1">{status.trackers.active}<span class="text-base font-normal text-[var(--color-muted-foreground)]"> / {status.trackers.total}</span></p>
+		</Card>
+		<Card>
+			<p class="text-sm text-[var(--color-muted-foreground)]">Targets</p>
+			<p class="text-3xl font-semibold mt-1">{status.targets}</p>
+		</Card>
+	</div>
+
+	<h3 class="text-lg font-medium mb-3">Recent Events</h3>
+	{#if status.recent_events.length === 0}
+		<Card>
+			<p class="text-sm text-[var(--color-muted-foreground)]">No events yet. Create a tracker to start monitoring albums.</p>
+		</Card>
+	{:else}
+		<Card>
+			<div class="divide-y divide-[var(--color-border)]">
+				{#each status.recent_events as event}
+					<div class="py-3 first:pt-0 last:pb-0">
+						<div class="flex items-center justify-between">
+							<div>
+								<span class="text-sm font-medium">{event.album_name}</span>
+								<span class="text-xs ml-2 px-1.5 py-0.5 rounded bg-[var(--color-muted)] text-[var(--color-muted-foreground)]">{event.event_type}</span>
+							</div>
+							<span class="text-xs text-[var(--color-muted-foreground)]">{new Date(event.created_at).toLocaleString()}</span>
+						</div>
+					</div>
+				{/each}
+			</div>
+		</Card>
+	{/if}
+{:else}
+	<p class="text-sm text-[var(--color-muted-foreground)]">Loading...</p>
+{/if}