test(dashboard): add missing tag tree mock to recentDocs reader test

The sequential mock chain in the recentDocs test was missing a 6th call
for /api/tags/tree added in the tag tree fetch. Without it the mock
returned undefined, causing settled() to throw and the outer catch to
return an empty recentDocs array.

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

CLAUDE.md

@@ -197,6 +197,7 @@ frontend/src/routes/
 ├── aktivitaeten/           Unified activity feed (Chronik)
 ├── geschichten/            Stories — list, [id], [id]/edit, new
 ├── stammbaum/              Family tree (Stammbaum)
+├── themen/                 Topics directory — browsable tag index
 ├── enrich/                 Enrichment workflow — [id], done
 ├── admin/                  User, group, tag, OCR, system management
 ├── hilfe/transkription/    Transcription help page

docs/architecture/c4/l3-frontend-3c-people-stories.puml

@@ -14,6 +14,7 @@ System_Boundary(frontend, "Web Frontend (SvelteKit / SSR)") {
     Component(geschichten, "/geschichten and /geschichten/[id]", "SvelteKit Routes", "Story list and detail pages. Loader: GET /api/geschichten?status=PUBLISHED.")
     Component(geschichtenEdit, "/geschichten/[id]/edit and /geschichten/new", "SvelteKit Routes", "Story editor with rich text, person and document linking. Actions: PUT/POST /api/geschichten. Requires BLOG_WRITE permission.")
     Component(stammbaum, "/stammbaum", "SvelteKit Route", "Family tree visualisation. Loader: GET /api/network (nodes + edges). Renders interactive family tree from network graph data.")
+    Component(themen, "/themen", "SvelteKit Route", "Browsable topic index. Shows all root tags as cards with color bars and child rows. ThemenWidget also embedded in the home dashboard (reader + editor sidebar). Loader: GET /api/tags/tree.")
     Component(profilePage, "/profile", "SvelteKit Route", "Current user profile settings. Loader: GET /api/users/me/notification-preferences. Actions: update name/password and notification preferences.")
     Component(userProfile, "/users/[id]", "SvelteKit Route", "Public user profile view. Loader: GET /api/users/{id}.")
 }
@@ -26,6 +27,7 @@ Rel(aktivitaeten, backend, "GET /api/dashboard/activity, GET /api/notifications"
 Rel(geschichten, backend, "GET /api/geschichten", "HTTP / JSON")
 Rel(geschichtenEdit, backend, "GET/PUT/POST /api/geschichten", "HTTP / JSON")
 Rel(stammbaum, backend, "GET /api/network", "HTTP / JSON")
+Rel(themen, backend, "GET /api/tags/tree", "HTTP / JSON")
 Rel(profilePage, backend, "GET/PUT /api/users/me, notification-preferences", "HTTP / JSON")
 Rel(userProfile, backend, "GET /api/users/{id}", "HTTP / JSON")
 

frontend/messages/de.json

@@ -1084,5 +1084,10 @@
 	"timeline_dragging_aria_live": "Zeitraum {from} bis {to} ausgewählt",
 	"error_page_id_label": "Fehler-ID",
 	"error_copy_id_label": "ID kopieren",
-	"error_copied": "Kopiert!"
+	"error_copied": "Kopiert!",
+	"themen_widget_title": "Themen",
+	"themen_alle": "Alle Themen",
+	"themen_leer": "Noch keine Themen vergeben.",
+	"themen_weitere": "+ {count} weitere",
+	"themen_dokumente": "{count} Dokumente"
 }

frontend/messages/en.json

@@ -1084,5 +1084,10 @@
 	"timeline_dragging_aria_live": "Range {from} to {to} selected",
 	"error_page_id_label": "Error ID",
 	"error_copy_id_label": "Copy ID",
-	"error_copied": "Copied!"
+	"error_copied": "Copied!",
+	"themen_widget_title": "Topics",
+	"themen_alle": "All Topics",
+	"themen_leer": "No topics assigned yet.",
+	"themen_weitere": "+ {count} more",
+	"themen_dokumente": "{count} documents"
 }

frontend/messages/es.json

@@ -1084,5 +1084,10 @@
 	"timeline_dragging_aria_live": "Rango {from} a {to} seleccionado",
 	"error_page_id_label": "ID de error",
 	"error_copy_id_label": "Copiar ID",
-	"error_copied": "¡Copiado!"
+	"error_copied": "¡Copiado!",
+	"themen_widget_title": "Temas",
+	"themen_alle": "Todos los temas",
+	"themen_leer": "Aún no hay temas.",
+	"themen_weitere": "+ {count} más",
+	"themen_dokumente": "{count} documentos"
 }

frontend/src/lib/shared/dashboard/ThemenWidget.svelte

@@ -0,0 +1,67 @@
+<script lang="ts">
+import * as m from '$lib/paraglide/messages.js';
+import type { components } from '$lib/generated/api';
+import { hasAnyDocuments } from '$lib/shared/utils/tagUtils';
+
+type TagTreeNodeDTO = components['schemas']['TagTreeNodeDTO'];
+
+interface Props {
+	tags: TagTreeNodeDTO[];
+	compact?: boolean;
+}
+
+const MAX_VISIBLE_TAGS = 6;
+
+const { tags, compact = false }: Props = $props();
+
+const visibleTags = $derived.by(() => tags.filter(hasAnyDocuments));
+const shownTags = $derived(visibleTags.slice(0, MAX_VISIBLE_TAGS));
+</script>
+
+<section class="rounded-sm border border-line bg-surface p-5 shadow-sm">
+	<div class="mb-4 flex items-center justify-between">
+		<h2 class="font-sans text-xs font-bold tracking-widest text-ink-3 uppercase">
+			{m.themen_widget_title()}
+		</h2>
+		<a
+			href="/themen"
+			class="flex min-h-[44px] items-center text-[11px] font-semibold text-ink-2 no-underline focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:outline-none"
+		>
+			{m.themen_alle()} →
+		</a>
+	</div>
+
+	{#if visibleTags.length === 0}
+		<p class="font-sans text-sm text-ink-3">{m.themen_leer()}</p>
+	{:else}
+		<div
+			class="grid gap-2 {compact ? 'grid-cols-1' : 'grid-cols-1 sm:grid-cols-2'}"
+			data-compact={compact}
+		>
+			{#each shownTags as tag (tag.id)}
+				<a
+					href="/documents?tag={encodeURIComponent(tag.name)}"
+					aria-label="{tag.name}{tag.documentCount > 0
+						? ', ' + m.themen_dokumente({ count: tag.documentCount })
+						: ''}"
+					class="flex cursor-pointer items-stretch overflow-hidden rounded-sm border border-line bg-canvas hover:bg-surface focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:outline-none"
+					style="min-height: 56px"
+				>
+					<span
+						class="w-1 flex-shrink-0 self-stretch"
+						aria-hidden="true"
+						style="background: var(--c-tag-{tag.color ?? 'slate'})"
+					></span>
+					<span class="flex min-w-0 flex-1 flex-col justify-center gap-0.5 px-3 py-3">
+						<span class="truncate font-serif text-sm font-semibold text-ink">{tag.name}</span>
+						{#if tag.documentCount > 0}
+							<span class="font-sans text-xs text-ink-3 tabular-nums">
+								{m.themen_dokumente({ count: tag.documentCount })}
+							</span>
+						{/if}
+					</span>
+				</a>
+			{/each}
+		</div>
+	{/if}
+</section>

frontend/src/lib/shared/dashboard/ThemenWidget.svelte.spec.ts

@@ -0,0 +1,58 @@
+import { describe, it, expect, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import ThemenWidget from './ThemenWidget.svelte';
+import type { components } from '$lib/generated/api';
+
+afterEach(() => {
+	cleanup();
+});
+
+type TagTreeNodeDTO = components['schemas']['TagTreeNodeDTO'];
+
+function makeTag(
+	name: string,
+	documentCount: number,
+	children: TagTreeNodeDTO[] = []
+): TagTreeNodeDTO {
+	return { id: 'id-' + name, name, documentCount, children };
+}
+
+describe('ThemenWidget', () => {
+	it('renders a card link per visible tag', async () => {
+		const tags = [makeTag('Briefe', 5), makeTag('Fotos', 3)];
+		const { getByRole } = render(ThemenWidget, { tags });
+		await expect.element(getByRole('link', { name: /Briefe/ })).toBeInTheDocument();
+		await expect.element(getByRole('link', { name: /Fotos/ })).toBeInTheDocument();
+	});
+
+	it('hides tags where no document exists in the subtree', async () => {
+		const tags = [makeTag('Briefe', 5), makeTag('Leer', 0)];
+		render(ThemenWidget, { tags });
+		expect(document.body.textContent).toContain('Briefe');
+		expect(document.body.textContent).not.toContain('Leer');
+	});
+
+	it('shows the empty state text when all tags are filtered out', async () => {
+		render(ThemenWidget, { tags: [makeTag('Leer', 0)] });
+		expect(document.body.textContent).toMatch(/Noch keine Themen/);
+	});
+
+	it('shows empty state when tags array is empty', async () => {
+		render(ThemenWidget, { tags: [] });
+		expect(document.body.textContent).toMatch(/Noch keine Themen/);
+	});
+
+	it('renders in compact single-column mode when compact prop is true', async () => {
+		const tags = [makeTag('Briefe', 5)];
+		const { container } = render(ThemenWidget, { tags, compact: true });
+		const grid = container.querySelector('[data-compact="true"]');
+		expect(grid).not.toBeNull();
+	});
+
+	it('links to "Alle Themen" page', async () => {
+		const tags = [makeTag('Briefe', 5)];
+		const { getByRole } = render(ThemenWidget, { tags });
+		const link = getByRole('link', { name: /Alle Themen/ });
+		await expect.element(link).toHaveAttribute('href', '/themen');
+	});
+});

frontend/src/lib/shared/utils/tagUtils.test.ts

@@ -0,0 +1,29 @@
+import { describe, it, expect } from 'vitest';
+import { hasAnyDocuments } from './tagUtils';
+import type { components } from '$lib/generated/api';
+
+type TagTreeNodeDTO = components['schemas']['TagTreeNodeDTO'];
+
+function makeNode(documentCount: number, children: TagTreeNodeDTO[] = []): TagTreeNodeDTO {
+	return { id: 'id', name: 'name', documentCount, children };
+}
+
+describe('hasAnyDocuments', () => {
+	it('returns false for a leaf node with documentCount=0', () => {
+		expect(hasAnyDocuments(makeNode(0))).toBe(false);
+	});
+
+	it('returns true for a leaf node with documentCount=3', () => {
+		expect(hasAnyDocuments(makeNode(3))).toBe(true);
+	});
+
+	it('returns true for a root with documentCount=0 but a child with documentCount=5', () => {
+		const node = makeNode(0, [makeNode(5)]);
+		expect(hasAnyDocuments(node)).toBe(true);
+	});
+
+	it('returns false for a root with documentCount=0 and all children also 0', () => {
+		const node = makeNode(0, [makeNode(0), makeNode(0)]);
+		expect(hasAnyDocuments(node)).toBe(false);
+	});
+});

frontend/src/lib/shared/utils/tagUtils.ts

@@ -0,0 +1,7 @@
+import type { components } from '$lib/generated/api';
+
+type TagTreeNodeDTO = components['schemas']['TagTreeNodeDTO'];
+
+export function hasAnyDocuments(node: TagTreeNodeDTO): boolean {
+	return (node.documentCount ?? 0) > 0 || (node.children ?? []).some(hasAnyDocuments);
+}

frontend/src/routes/+page.server.ts

@@ -12,6 +12,7 @@ type IncompleteDocumentDTO = components['schemas']['IncompleteDocumentDTO'];
 type PersonSummaryDTO = components['schemas']['PersonSummaryDTO'];
 type DocumentListItem = components['schemas']['DocumentListItem'];
 type Geschichte = components['schemas']['Geschichte'];
+type TagTreeNodeDTO = components['schemas']['TagTreeNodeDTO'];
 
 function settled<T>(res: PromiseSettledResult<unknown> | undefined): T | null {
 	if (res?.status !== 'fulfilled') return null;
@@ -40,7 +41,8 @@ export async function load({ fetch, parent }) {
 				api.GET('/api/documents/search', {
 					params: { query: { sort: 'UPDATED_AT', dir: 'DESC', size: 5 } }
 				}),
-				api.GET('/api/geschichten', { params: { query: { status: 'PUBLISHED', limit: 3 } } })
+				api.GET('/api/geschichten', { params: { query: { status: 'PUBLISHED', limit: 3 } } }),
+				api.GET('/api/tags/tree')
 			];
 			if (canBlogWrite) {
 				readerFetches.push(
@@ -48,7 +50,7 @@ export async function load({ fetch, parent }) {
 				);
 			}
 
-			const [statsRes, topPersonsRes, recentDocsRes, recentStoriesRes, draftsRes] =
+			const [statsRes, topPersonsRes, recentDocsRes, recentStoriesRes, tagTreeRes, draftsRes] =
 				await Promise.allSettled(readerFetches);
 
 			const readerStats = settled<StatsDTO>(statsRes);
@@ -56,6 +58,7 @@ export async function load({ fetch, parent }) {
 			const searchData = settled<{ items: DocumentListItem[] }>(recentDocsRes);
 			const recentDocs = searchData?.items ?? [];
 			const recentStories = settled<Geschichte[]>(recentStoriesRes) ?? [];
+			const tagTree = settled<TagTreeNodeDTO[]>(tagTreeRes) ?? [];
 			const drafts = settled<Geschichte[]>(draftsRes) ?? [];
 
 			return {
@@ -65,6 +68,7 @@ export async function load({ fetch, parent }) {
 				topPersons,
 				recentDocs,
 				recentStories,
+				tagTree,
 				drafts,
 				error: null as string | null
 			};
@@ -80,7 +84,8 @@ export async function load({ fetch, parent }) {
 			readyResult,
 			weeklyStatsResult,
 			incompleteResult,
-			incompleteCountResult
+			incompleteCountResult,
+			tagTreeResult
 		] = await Promise.allSettled([
 			api.GET('/api/stats'),
 			api.GET('/api/dashboard/resume'),
@@ -91,7 +96,8 @@ export async function load({ fetch, parent }) {
 			api.GET('/api/transcription/ready-to-read'),
 			api.GET('/api/transcription/weekly-stats'),
 			api.GET('/api/documents/incomplete', { params: { query: { size: 5 } } }),
-			api.GET('/api/documents/incomplete-count')
+			api.GET('/api/documents/incomplete-count'),
+			api.GET('/api/tags/tree')
 		]);
 
 		let stats: StatsDTO | null = null;
@@ -104,6 +110,7 @@ export async function load({ fetch, parent }) {
 		let weeklyStats: TranscriptionWeeklyStatsDTO | null = null;
 		let incompleteDocs: IncompleteDocumentDTO[] = [];
 		let incompleteTotal = 0;
+		let tagTree: TagTreeNodeDTO[] = [];
 
 		if (statsResult.status === 'fulfilled' && statsResult.value.response.ok) {
 			stats = statsResult.value.data ?? null;
@@ -135,6 +142,9 @@ export async function load({ fetch, parent }) {
 		if (incompleteCountResult.status === 'fulfilled' && incompleteCountResult.value.response.ok) {
 			incompleteTotal = (incompleteCountResult.value.data?.count as number | undefined) ?? 0;
 		}
+		if (tagTreeResult.status === 'fulfilled' && tagTreeResult.value.response.ok) {
+			tagTree = (tagTreeResult.value.data as TagTreeNodeDTO[]) ?? [];
+		}
 
 		return {
 			isReader: false as const,
@@ -148,6 +158,7 @@ export async function load({ fetch, parent }) {
 			weeklyStats,
 			incompleteDocs,
 			incompleteTotal,
+			tagTree,
 			error: null as string | null
 		};
 	} catch (e) {
@@ -169,6 +180,7 @@ export async function load({ fetch, parent }) {
 			topPersons: [] as PersonSummaryDTO[],
 			recentDocs: [] as DocumentListItem[],
 			recentStories: [] as Geschichte[],
+			tagTree: [] as TagTreeNodeDTO[],
 			drafts: [] as Geschichte[],
 			error: 'Daten konnten nicht geladen werden.' as string | null
 		};

frontend/src/routes/+page.svelte

@@ -10,6 +10,7 @@ import ReaderPersonChips from '$lib/shared/dashboard/ReaderPersonChips.svelte';
 import ReaderDraftsModule from '$lib/shared/dashboard/ReaderDraftsModule.svelte';
 import ReaderRecentDocs from '$lib/shared/dashboard/ReaderRecentDocs.svelte';
 import ReaderRecentStories from '$lib/shared/dashboard/ReaderRecentStories.svelte';
+import ThemenWidget from '$lib/shared/dashboard/ThemenWidget.svelte';
 import { m } from '$lib/paraglide/messages.js';
 
 let { data } = $props();
@@ -45,6 +46,8 @@ const greetingText = $derived.by(() => {
 
 			<ReaderPersonChips persons={data.topPersons ?? []} />
 
+			<ThemenWidget tags={data.tagTree ?? []} />
+
 			<div class="grid grid-cols-1 gap-1.5 sm:grid-cols-2">
 				<ReaderRecentDocs documents={data.recentDocs ?? []} />
 				<ReaderRecentStories stories={data.recentStories ?? []} />
@@ -56,36 +59,40 @@ const greetingText = $derived.by(() => {
 				<h1 class="font-serif text-[2rem] text-ink">{greetingText}</h1>
 			</div>
 		{/if}
-		<div class="grid grid-cols-1 gap-5 lg:grid-cols-[1fr_320px] lg:items-start">
-			<div class="flex flex-col gap-5">
-				<DashboardResumeStrip resumeDoc={data.resumeDoc ?? null} />
+		<div class="flex flex-col gap-5">
+			<DashboardResumeStrip resumeDoc={data.resumeDoc ?? null} />
 
-				<EnrichmentBlock
-					topDocs={data.incompleteDocs ?? []}
-					totalCount={data.incompleteTotal ?? 0}
-					bannerCount={bannerCount}
-					onBannerClose={() => (bannerCount = 0)}
-				/>
+			<ThemenWidget tags={data.tagTree ?? []} />
 
-				<section aria-label={m.dashboard_mission_caption()}>
-					<h2 class="mb-3 font-sans text-xs font-bold tracking-widest text-ink-3 uppercase">
-						{m.dashboard_mission_caption()}
-					</h2>
-					<MissionControlStrip
-						segmentationDocs={data.segmentationDocs ?? []}
-						transcriptionDocs={data.transcriptionDocs ?? []}
-						readyDocs={data.readyDocs ?? []}
-						weeklyStats={data.weeklyStats ?? null}
+			<div class="grid grid-cols-1 gap-5 lg:grid-cols-[1fr_320px] lg:items-start">
+				<div class="flex flex-col gap-5">
+					<EnrichmentBlock
+						topDocs={data.incompleteDocs ?? []}
+						totalCount={data.incompleteTotal ?? 0}
+						bannerCount={bannerCount}
+						onBannerClose={() => (bannerCount = 0)}
 					/>
-				</section>
-			</div>
 
-			<div class="flex flex-col gap-5 lg:sticky lg:top-[80px]">
-				<DashboardFamilyPulse pulse={data.pulse ?? null} />
-				<DashboardActivityFeed feed={data.activityFeed ?? []} />
-				{#if data.canWrite}
-					<DropZone onUploadComplete={(count) => (bannerCount = count)} />
-				{/if}
+					<section aria-label={m.dashboard_mission_caption()}>
+						<h2 class="mb-3 font-sans text-xs font-bold tracking-widest text-ink-3 uppercase">
+							{m.dashboard_mission_caption()}
+						</h2>
+						<MissionControlStrip
+							segmentationDocs={data.segmentationDocs ?? []}
+							transcriptionDocs={data.transcriptionDocs ?? []}
+							readyDocs={data.readyDocs ?? []}
+							weeklyStats={data.weeklyStats ?? null}
+						/>
+					</section>
+				</div>
+
+				<div class="flex flex-col gap-5 lg:sticky lg:top-[80px]">
+					<DashboardFamilyPulse pulse={data.pulse ?? null} />
+					<DashboardActivityFeed feed={data.activityFeed ?? []} />
+					{#if data.canWrite}
+						<DropZone onUploadComplete={(count) => (bannerCount = count)} />
+					{/if}
+				</div>
 			</div>
 		</div>
 	{/if}

frontend/src/routes/page.server.spec.ts

@@ -108,7 +108,8 @@ describe('home page load — dashboard', () => {
 				data: { segmentationCount: 0, transcriptionCount: 0, readyCount: 0 }
 			}) // weekly-stats
 			.mockResolvedValueOnce({ response: { ok: true }, data: [] }) // incomplete
-			.mockResolvedValueOnce({ response: { ok: true }, data: { count: 0 } }); // incomplete-count
+			.mockResolvedValueOnce({ response: { ok: true }, data: { count: 0 } }) // incomplete-count
+			.mockResolvedValueOnce({ response: { ok: true }, data: [] }); // tags/tree
 		vi.mocked(createApiClient).mockReturnValue({ GET: mockGet } as ReturnType<
 			typeof createApiClient
 		>);
@@ -146,7 +147,8 @@ describe('home page load — dashboard', () => {
 				data: { segmentationCount: 0, transcriptionCount: 0, readyCount: 0 }
 			}) // weekly-stats
 			.mockResolvedValueOnce({ response: { ok: true }, data: [] }) // incomplete
-			.mockResolvedValueOnce({ response: { ok: true }, data: { count: 0 } }); // incomplete-count
+			.mockResolvedValueOnce({ response: { ok: true }, data: { count: 0 } }) // incomplete-count
+			.mockResolvedValueOnce({ response: { ok: true }, data: [] }); // tags/tree
 		vi.mocked(createApiClient).mockReturnValue({ GET: mockGet } as ReturnType<
 			typeof createApiClient
 		>);
@@ -419,7 +421,8 @@ describe('home page load — reader branch (isReader = !canWrite && !canAnnotate
 				response: { ok: true },
 				data: { items: [searchItem], totalElements: 1, pageNumber: 0, pageSize: 5, totalPages: 1 }
 			}) // search
-			.mockResolvedValueOnce({ response: { ok: true }, data: [] }); // stories
+			.mockResolvedValueOnce({ response: { ok: true }, data: [] }) // stories
+			.mockResolvedValueOnce({ response: { ok: true }, data: [] }); // tags/tree
 		vi.mocked(createApiClient).mockReturnValue({ GET: mockGet } as ReturnType<
 			typeof createApiClient
 		>);
@@ -458,7 +461,8 @@ describe('home page load — reader branch (isReader = !canWrite && !canAnnotate
 			.mockResolvedValueOnce(okStats)
 			.mockReturnValueOnce(failPersons)
 			.mockResolvedValueOnce(okSearch)
-			.mockResolvedValueOnce(okStories);
+			.mockResolvedValueOnce(okStories)
+			.mockResolvedValueOnce({ response: { ok: true, status: 200 }, data: [] }); // tags/tree
 		vi.mocked(createApiClient).mockReturnValue({ GET: mockGet } as ReturnType<
 			typeof createApiClient
 		>);

frontend/src/routes/themen/+page.server.ts

@@ -0,0 +1,12 @@
+import { error } from '@sveltejs/kit';
+import { createApiClient } from '$lib/shared/api.server';
+import type { components } from '$lib/generated/api';
+
+type TagTreeNodeDTO = components['schemas']['TagTreeNodeDTO'];
+
+export async function load({ fetch }: Parameters<import('./$types').PageServerLoad>[0]) {
+	const api = createApiClient(fetch);
+	const result = await api.GET('/api/tags/tree');
+	if (!result.response.ok) throw error(500, 'Themen konnten nicht geladen werden.');
+	return { tree: (result.data ?? []) as TagTreeNodeDTO[] };
+}

frontend/src/routes/themen/+page.svelte

@@ -0,0 +1,85 @@
+<script lang="ts">
+import * as m from '$lib/paraglide/messages.js';
+import BackButton from '$lib/shared/primitives/BackButton.svelte';
+import { hasAnyDocuments } from '$lib/shared/utils/tagUtils';
+import type { components } from '$lib/generated/api';
+
+type TagTreeNodeDTO = components['schemas']['TagTreeNodeDTO'];
+
+const MAX_VISIBLE_CHILDREN = 5;
+
+let { data }: { data: { tree: TagTreeNodeDTO[] } } = $props();
+
+const visibleTree = $derived.by(() => data.tree.filter(hasAnyDocuments));
+</script>
+
+<svelte:head>
+	<title>{m.themen_widget_title()}</title>
+</svelte:head>
+
+<main class="mx-auto max-w-7xl px-4 py-8 sm:px-6 lg:px-8">
+	<div class="mb-6 flex items-center gap-3">
+		<BackButton />
+		<h1 class="font-serif text-2xl font-semibold text-ink">{m.themen_widget_title()}</h1>
+	</div>
+
+	{#if visibleTree.length === 0}
+		<p class="font-sans text-sm text-ink-3">{m.themen_leer()}</p>
+	{:else}
+		<div class="grid grid-cols-1 gap-4 sm:grid-cols-2 lg:grid-cols-3">
+			{#each visibleTree as tag (tag.id)}
+				{@const visibleChildren = (tag.children ?? []).filter(hasAnyDocuments)}
+				{@const shownChildren = visibleChildren.slice(0, MAX_VISIBLE_CHILDREN)}
+				{@const hiddenCount = visibleChildren.length - shownChildren.length}
+
+				<div class="overflow-hidden rounded-sm border border-line bg-surface shadow-sm">
+					<div
+						class="h-1.5 w-full flex-shrink-0"
+						aria-hidden="true"
+						style="background: var(--c-tag-{tag.color ?? 'slate'})"
+					></div>
+
+					<a
+						href="/documents?tag={encodeURIComponent(tag.name)}"
+						aria-label="{tag.name}{tag.documentCount > 0
+							? ', ' + m.themen_dokumente({ count: tag.documentCount })
+							: ''}"
+						class="flex min-h-[56px] items-center justify-between px-4 pt-4 pb-3 hover:bg-canvas focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:outline-none focus-visible:ring-inset"
+					>
+						<span class="font-serif text-base font-semibold text-ink">{tag.name}</span>
+						<span class="mr-1 ml-auto font-sans text-sm text-ink-3 tabular-nums">
+							{#if tag.documentCount > 0}{tag.documentCount}{/if}
+						</span>
+						<span aria-hidden="true" class="h-3.5 w-3.5 flex-shrink-0 text-brand-mint">›</span>
+					</a>
+
+					{#if shownChildren.length > 0}
+						<div class="mx-4 border-t border-line"></div>
+
+						{#each shownChildren as child (child.id)}
+							<a
+								href="/documents?tag={encodeURIComponent(child.name)}"
+								class="flex min-h-[44px] items-center justify-between px-4 py-2.5 hover:bg-canvas focus-visible:bg-canvas focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:outline-none focus-visible:ring-inset"
+							>
+								<span class="font-sans text-sm text-ink">{child.name}</span>
+								<span class="mr-1 ml-auto font-sans text-xs text-ink-3 tabular-nums">
+									{#if child.documentCount > 0}{child.documentCount}{/if}
+								</span>
+								<span aria-hidden="true" class="h-3 w-3 flex-shrink-0 text-brand-mint">›</span>
+							</a>
+						{/each}
+
+						{#if hiddenCount > 0}
+							<a
+								href="/documents?tag={encodeURIComponent(tag.name)}"
+								class="block min-h-[44px] px-4 py-2.5 font-sans text-sm text-ink-3 hover:bg-canvas hover:text-ink focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:outline-none focus-visible:ring-inset"
+							>
+								{m.themen_weitere({ count: hiddenCount })} →
+							</a>
+						{/if}
+					{/if}
+				</div>
+			{/each}
+		</div>
+	{/if}
+</main>

frontend/src/routes/themen/page.server.spec.ts

@@ -0,0 +1,60 @@
+import { describe, expect, it, vi, beforeEach } from 'vitest';
+
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
+
+import { createApiClient } from '$lib/shared/api.server';
+
+beforeEach(() => vi.clearAllMocks());
+
+function mockApiGet(ok: boolean, data: unknown) {
+	vi.mocked(createApiClient).mockReturnValue({
+		GET: vi.fn().mockResolvedValue({ response: { ok }, data })
+	} as ReturnType<typeof createApiClient>);
+}
+
+const makeTag = (name: string, documentCount = 0) => ({
+	id: 'id-' + name,
+	name,
+	documentCount,
+	children: []
+});
+
+describe('/themen +page.server load', () => {
+	function makeLoadEvent() {
+		return {
+			fetch: vi.fn() as unknown as typeof fetch,
+			request: new Request('http://localhost/themen'),
+			url: new URL('http://localhost/themen')
+		};
+	}
+
+	it('returns tag tree when API succeeds', async () => {
+		const tree = [makeTag('Briefe', 5), makeTag('Fotos', 3)];
+		mockApiGet(true, tree);
+
+		const { load } = await import('./+page.server');
+		const result = await load(makeLoadEvent());
+
+		expect(result.tree).toEqual(tree);
+	});
+
+	it('returns empty array when API returns empty list', async () => {
+		mockApiGet(true, []);
+
+		const { load } = await import('./+page.server');
+		const result = await load(makeLoadEvent());
+
+		expect(result.tree).toEqual([]);
+	});
+
+	it('throws 500 when API call fails', async () => {
+		mockApiGet(false, null);
+
+		const { load } = await import('./+page.server');
+
+		await expect(load(makeLoadEvent())).rejects.toMatchObject({ status: 500 });
+	});
+});

frontend/src/routes/themen/page.svelte.spec.ts

@@ -0,0 +1,57 @@
+import { describe, it, expect, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import ThemenPage from './+page.svelte';
+import type { components } from '$lib/generated/api';
+
+afterEach(() => {
+	cleanup();
+});
+
+type TagTreeNodeDTO = components['schemas']['TagTreeNodeDTO'];
+
+function makeTag(
+	name: string,
+	documentCount: number,
+	children: TagTreeNodeDTO[] = []
+): TagTreeNodeDTO {
+	return { id: 'id-' + name, name, documentCount, children };
+}
+
+describe('/themen +page', () => {
+	it('renders one card per visible root tag', async () => {
+		const tree = [makeTag('Briefe', 5), makeTag('Fotos', 3)];
+		render(ThemenPage, { data: { tree } });
+		expect(document.body.textContent).toContain('Briefe');
+		expect(document.body.textContent).toContain('Fotos');
+	});
+
+	it('does not render a tag with no documents in its subtree', async () => {
+		const tree = [makeTag('Briefe', 5), makeTag('Leer', 0)];
+		render(ThemenPage, { data: { tree } });
+		expect(document.body.textContent).not.toContain('Leer');
+	});
+
+	it('shows empty state when all tags filtered out', async () => {
+		render(ThemenPage, { data: { tree: [makeTag('Leer', 0)] } });
+		expect(document.body.textContent).toMatch(/Noch keine Themen/);
+	});
+
+	it('shows empty state when tree is empty', async () => {
+		render(ThemenPage, { data: { tree: [] } });
+		expect(document.body.textContent).toMatch(/Noch keine Themen/);
+	});
+
+	it('renders child tags for a root tag', async () => {
+		const tree = [makeTag('Briefe', 5, [makeTag('Brautbriefe', 3), makeTag('Kriegsbriefe', 2)])];
+		render(ThemenPage, { data: { tree } });
+		expect(document.body.textContent).toContain('Brautbriefe');
+		expect(document.body.textContent).toContain('Kriegsbriefe');
+	});
+
+	it('shows "+ N weitere" when a root tag has more than 5 children', async () => {
+		const children = Array.from({ length: 7 }, (_, i) => makeTag(`Kind${i}`, i + 1));
+		const tree = [makeTag('Briefe', 10, children)];
+		render(ThemenPage, { data: { tree } });
+		expect(document.body.textContent).toMatch(/\+\s*2\s*weitere/);
+	});
+});