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/+layout.svelte

@@ -0,0 +1,90 @@
+<script lang="ts">
+	import '../app.css';
+	import { page } from '$app/state';
+	import { goto } from '$app/navigation';
+	import { onMount } from 'svelte';
+	import { getAuth, loadUser, logout } from '$lib/auth.svelte';
+
+	let { children } = $props();
+	const auth = getAuth();
+
+	const navItems = [
+		{ href: '/', label: 'Dashboard', icon: '⊞' },
+		{ href: '/servers', label: 'Servers', icon: '⬡' },
+		{ href: '/trackers', label: 'Trackers', icon: '◎' },
+		{ href: '/templates', label: 'Templates', icon: '⎘' },
+		{ href: '/targets', label: 'Targets', icon: '◇' },
+	];
+
+	const isAuthPage = $derived(
+		page.url.pathname === '/login' || page.url.pathname === '/setup'
+	);
+
+	onMount(async () => {
+		await loadUser();
+		if (!auth.user && !isAuthPage) {
+			goto('/login');
+		}
+	});
+</script>
+
+{#if isAuthPage || auth.loading}
+	{@render children()}
+{:else if auth.user}
+	<div class="flex h-screen">
+		<!-- Sidebar -->
+		<aside class="w-56 border-r border-[var(--color-border)] bg-[var(--color-card)] flex flex-col">
+			<div class="p-4 border-b border-[var(--color-border)]">
+				<h1 class="text-base font-semibold tracking-tight">Immich Watcher</h1>
+				<p class="text-xs text-[var(--color-muted-foreground)] mt-0.5">Album notifications</p>
+			</div>
+			<nav class="flex-1 p-2 space-y-0.5">
+				{#each navItems as item}
+					<a
+						href={item.href}
+						class="flex items-center gap-2 px-3 py-2 rounded-md text-sm transition-colors
+							{page.url.pathname === item.href
+								? 'bg-[var(--color-accent)] text-[var(--color-accent-foreground)] font-medium'
+								: 'text-[var(--color-muted-foreground)] hover:bg-[var(--color-accent)] hover:text-[var(--color-accent-foreground)]'}"
+					>
+						<span class="text-base">{item.icon}</span>
+						{item.label}
+					</a>
+				{/each}
+				{#if auth.isAdmin}
+					<a
+						href="/users"
+						class="flex items-center gap-2 px-3 py-2 rounded-md text-sm transition-colors
+							{page.url.pathname === '/users'
+								? 'bg-[var(--color-accent)] text-[var(--color-accent-foreground)] font-medium'
+								: 'text-[var(--color-muted-foreground)] hover:bg-[var(--color-accent)] hover:text-[var(--color-accent-foreground)]'}"
+					>
+						<span class="text-base">⊕</span>
+						Users
+					</a>
+				{/if}
+			</nav>
+			<div class="p-3 border-t border-[var(--color-border)]">
+				<div class="flex items-center justify-between">
+					<div>
+						<p class="text-sm font-medium">{auth.user.username}</p>
+						<p class="text-xs text-[var(--color-muted-foreground)]">{auth.user.role}</p>
+					</div>
+					<button
+						onclick={logout}
+						class="text-xs text-[var(--color-muted-foreground)] hover:text-[var(--color-foreground)] transition-colors"
+					>
+						Logout
+					</button>
+				</div>
+			</div>
+		</aside>
+
+		<!-- Main content -->
+		<main class="flex-1 overflow-auto">
+			<div class="max-w-5xl mx-auto p-6">
+				{@render children()}
+			</div>
+		</main>
+	</div>
+{/if}