feat(dashboard): add EnrichmentBlock wrapper component

Composes UploadSuccessBanner + DashboardNeedsMetadata and reserves a
360px skeleton while \$navigating re-runs the loader with a fresh
incomplete list. Prevents the layout-shift jump after a batch upload
(Leonie's resolved decision #3 on issue #296).

Renders nothing when there is nothing to show — keeps the clean empty
dashboard.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/EnrichmentBlock.svelte

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+<script lang="ts">
+import { navigating } from '$app/stores';
+import DashboardNeedsMetadata from './DashboardNeedsMetadata.svelte';
+import UploadSuccessBanner from './UploadSuccessBanner.svelte';
+
+type IncompleteDoc = {
+	id: string;
+	title: string;
+	uploadedAt: string;
+};
+
+interface Props {
+	topDocs: IncompleteDoc[];
+	totalCount: number;
+	bannerCount: number;
+	onBannerClose: () => void;
+}
+
+let { topDocs, totalCount, bannerCount, onBannerClose }: Props = $props();
+
+const showSkeleton = $derived(!!$navigating && topDocs.length === 0);
+const showBlock = $derived(topDocs.length > 0 || bannerCount > 0 || showSkeleton);
+</script>
+
+{#if showBlock}
+	<div data-testid="enrichment-block" class="flex flex-col gap-3">
+		{#if bannerCount > 0}
+			<UploadSuccessBanner count={bannerCount} onClose={onBannerClose} />
+		{/if}
+		{#if topDocs.length > 0}
+			<DashboardNeedsMetadata topDocs={topDocs} totalCount={totalCount} />
+		{:else if showSkeleton}
+			<div
+				class="h-[360px] animate-pulse rounded-sm border border-line bg-surface/50 motion-reduce:animate-none"
+				aria-hidden="true"
+			></div>
+		{/if}
+	</div>
+{/if}

frontend/src/lib/components/EnrichmentBlock.svelte.spec.ts

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+import { describe, it, expect, afterEach, vi } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+
+import EnrichmentBlock from './EnrichmentBlock.svelte';
+
+vi.mock('$app/stores', async () => {
+	const { writable } = await import('svelte/store');
+	return { navigating: writable(null) };
+});
+
+afterEach(cleanup);
+
+type Doc = { id: string; title: string; uploadedAt: string };
+
+function doc(id: string, title = 'Doc'): Doc {
+	return { id, title, uploadedAt: '2026-04-20T12:00:00' };
+}
+
+describe('EnrichmentBlock', () => {
+	it('renders nothing when topDocs is empty and banner count is 0', async () => {
+		render(EnrichmentBlock, {
+			topDocs: [],
+			totalCount: 0,
+			bannerCount: 0,
+			onBannerClose: vi.fn()
+		});
+		await expect.element(page.getByTestId('enrichment-block')).not.toBeInTheDocument();
+	});
+
+	it('renders the list component when topDocs is non-empty', async () => {
+		render(EnrichmentBlock, {
+			topDocs: [doc('d1')],
+			totalCount: 1,
+			bannerCount: 0,
+			onBannerClose: vi.fn()
+		});
+		await expect.element(page.getByTestId('dashboard-needs-metadata')).toBeInTheDocument();
+	});
+
+	it('renders the banner when bannerCount > 0', async () => {
+		render(EnrichmentBlock, {
+			topDocs: [],
+			totalCount: 0,
+			bannerCount: 3,
+			onBannerClose: vi.fn()
+		});
+		await expect.element(page.getByRole('status')).toBeInTheDocument();
+	});
+
+	it('composes banner + list when both are present', async () => {
+		render(EnrichmentBlock, {
+			topDocs: [doc('d1')],
+			totalCount: 1,
+			bannerCount: 2,
+			onBannerClose: vi.fn()
+		});
+		await expect.element(page.getByRole('status')).toBeInTheDocument();
+		await expect.element(page.getByTestId('dashboard-needs-metadata')).toBeInTheDocument();
+	});
+});