feat(TRUEREF-0015): implement web UI repository dashboard

- Repository list with state badges, stats, and action buttons
- Add repository modal for GitHub URLs and local paths
- Live indexing progress bar polling every 2s
- Confirm dialog for destructive actions
- Repository detail page with versions and recent jobs
- Settings page placeholder

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/routes/+layout.svelte

@@ -5,5 +5,42 @@
 	let { children } = $props();
 </script>
 
-<svelte:head><link rel="icon" href={favicon} /></svelte:head>
-{@render children()}
+<svelte:head>
+	<link rel="icon" href={favicon} />
+	<title>TrueRef</title>
+</svelte:head>
+
+<div class="min-h-screen bg-gray-50">
+	<nav class="border-b border-gray-200 bg-white">
+		<div class="mx-auto max-w-6xl px-4 sm:px-6 lg:px-8">
+			<div class="flex h-14 items-center justify-between">
+				<div class="flex items-center gap-6">
+					<a href="/" class="flex items-center gap-2 font-semibold text-gray-900">
+						<svg
+							class="h-6 w-6 text-blue-600"
+							viewBox="0 0 24 24"
+							fill="none"
+							stroke="currentColor"
+							stroke-width="2"
+						>
+							<path
+								stroke-linecap="round"
+								stroke-linejoin="round"
+								d="M12 6.253v13m0-13C10.832 5.477 9.246 5 7.5 5S4.168 5.477 3 6.253v13C4.168 18.477 5.754 18 7.5 18s3.332.477 4.5 1.253m0-13C13.168 5.477 14.754 5 16.5 5c1.747 0 3.332.477 4.5 1.253v13C19.832 18.477 18.247 18 16.5 18c-1.746 0-3.332.477-4.5 1.253"
+							/>
+						</svg>
+						<span>TrueRef</span>
+					</a>
+					<a href="/" class="text-sm text-gray-600 hover:text-gray-900"> Repositories </a>
+					<a href="/search" class="text-sm text-gray-600 hover:text-gray-900"> Search </a>
+					<a href="/settings" class="text-sm text-gray-600 hover:text-gray-900"> Settings </a>
+				</div>
+				<span class="text-xs text-gray-400">Self-hosted documentation intelligence</span>
+			</div>
+		</div>
+	</nav>
+
+	<main class="mx-auto max-w-6xl px-4 py-8 sm:px-6 lg:px-8">
+		{@render children()}
+	</main>
+</div>