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.spec.ts

@@ -0,0 +1,61 @@
+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();
+	});
+});