feat(admin): mass import card on system tab with live status polling

Adds a new card on the System tab that triggers the existing
POST /api/admin/trigger-import endpoint. Status is polled every 2 s
while RUNNING and stops automatically on DONE or FAILED.
IDLE/RUNNING/DONE/FAILED states each render distinct UI feedback.

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

frontend/messages/de.json

@@ -273,6 +273,14 @@
 	"admin_system_backfill_hashes_description": "Berechnet den SHA-256-Hash für alle bereits hochgeladenen Dokumente, die noch keinen Hash haben. Dadurch werden Annotationen korrekt mit ihrer Dateiversion verknüpft und wieder angezeigt.",
 	"admin_system_backfill_hashes_btn": "Datei-Hashes berechnen",
 	"admin_system_backfill_hashes_success": "{count} Dokumente wurden aktualisiert.",
+	"admin_system_import_heading": "Massenimport",
+	"admin_system_import_description": "Importiert Dokumente und Metadaten aus der Importdatei im /import-Verzeichnis.",
+	"admin_system_import_btn_start": "Import starten",
+	"admin_system_import_btn_retry": "Erneut starten",
+	"admin_system_import_status_idle": "Kein Import gestartet.",
+	"admin_system_import_status_running": "Import läuft…",
+	"admin_system_import_status_done": "Import abgeschlossen – {count} Dokumente verarbeitet.",
+	"admin_system_import_status_failed": "Fehler: {message}",
 	"comp_expandable_show_more": "Mehr anzeigen",
 	"comp_expandable_show_less": "Weniger anzeigen",
 	"error_comment_not_found": "Der Kommentar wurde nicht gefunden.",

frontend/messages/en.json

@@ -273,6 +273,14 @@
 	"admin_system_backfill_hashes_description": "Computes the SHA-256 hash for all previously uploaded documents that do not have one yet. This ensures annotations are correctly linked to their file version and shown again.",
 	"admin_system_backfill_hashes_btn": "Compute file hashes",
 	"admin_system_backfill_hashes_success": "{count} documents were updated.",
+	"admin_system_import_heading": "Mass import",
+	"admin_system_import_description": "Imports documents and metadata from the spreadsheet file in the /import directory.",
+	"admin_system_import_btn_start": "Start import",
+	"admin_system_import_btn_retry": "Start again",
+	"admin_system_import_status_idle": "No import started.",
+	"admin_system_import_status_running": "Import running…",
+	"admin_system_import_status_done": "Import complete – {count} documents processed.",
+	"admin_system_import_status_failed": "Error: {message}",
 	"comp_expandable_show_more": "Show more",
 	"comp_expandable_show_less": "Show less",
 	"error_comment_not_found": "The comment could not be found.",

frontend/messages/es.json

@@ -273,6 +273,14 @@
 	"admin_system_backfill_hashes_description": "Calcula el hash SHA-256 para todos los documentos ya subidos que aún no tienen uno. Así las anotaciones se vinculan correctamente a su versión del archivo y vuelven a mostrarse.",
 	"admin_system_backfill_hashes_btn": "Calcular hashes de archivo",
 	"admin_system_backfill_hashes_success": "{count} documentos fueron actualizados.",
+	"admin_system_import_heading": "Importación masiva",
+	"admin_system_import_description": "Importa documentos y metadatos desde el archivo en el directorio /import.",
+	"admin_system_import_btn_start": "Iniciar importación",
+	"admin_system_import_btn_retry": "Iniciar de nuevo",
+	"admin_system_import_status_idle": "No hay importación iniciada.",
+	"admin_system_import_status_running": "Importación en curso…",
+	"admin_system_import_status_done": "Importación completada – {count} documentos procesados.",
+	"admin_system_import_status_failed": "Error: {message}",
 	"comp_expandable_show_more": "Mostrar más",
 	"comp_expandable_show_less": "Mostrar menos",
 	"error_comment_not_found": "El comentario no pudo encontrarse.",

frontend/src/routes/admin/system/+page.svelte

@@ -6,6 +6,55 @@ let backfillLoading = $state(false);
 let backfillHashesResult: number | null = $state(null);
 let backfillHashesLoading = $state(false);
 
+type ImportStatus = {
+	state: 'IDLE' | 'RUNNING' | 'DONE' | 'FAILED';
+	message: string;
+	processed: number;
+	startedAt: string | null;
+};
+
+let importStatus: ImportStatus | null = $state(null);
+let pollInterval: ReturnType<typeof setInterval> | null = null;
+
+function startPolling() {
+	if (pollInterval) return;
+	pollInterval = setInterval(fetchImportStatus, 2000);
+}
+
+function stopPolling() {
+	if (pollInterval) {
+		clearInterval(pollInterval);
+		pollInterval = null;
+	}
+}
+
+async function fetchImportStatus() {
+	const res = await fetch('/api/admin/import-status');
+	if (res.ok) {
+		importStatus = await res.json();
+		if (importStatus!.state === 'RUNNING') {
+			startPolling();
+		} else {
+			stopPolling();
+		}
+	}
+}
+
+async function triggerImport() {
+	const res = await fetch('/api/admin/trigger-import', { method: 'POST' });
+	if (res.ok) {
+		importStatus = await res.json();
+		if (importStatus!.state === 'RUNNING') {
+			startPolling();
+		}
+	}
+}
+
+$effect(() => {
+	fetchImportStatus();
+	return () => stopPolling();
+});
+
 async function backfillVersions() {
 	backfillLoading = true;
 	backfillResult = null;
@@ -74,5 +123,48 @@ async function backfillFileHashes() {
 				</p>
 			{/if}
 		</div>
+
+		<!-- Mass import -->
+		<div class="rounded-sm border border-line bg-surface p-6 shadow-sm">
+			<h2 class="mb-1 font-sans text-sm font-bold text-ink">{m.admin_system_import_heading()}</h2>
+			<p class="mb-4 text-sm text-ink-2">{m.admin_system_import_description()}</p>
+
+			{#if importStatus?.state === 'RUNNING'}
+				<p class="text-sm text-ink-2">{m.admin_system_import_status_running()}</p>
+			{:else if importStatus?.state === 'DONE'}
+				<p class="mb-4 rounded-sm border border-green-200 bg-green-50 p-3 text-sm text-green-700">
+					{m.admin_system_import_status_done({ count: importStatus.processed })}
+				</p>
+				<button
+					data-import-trigger
+					onclick={triggerImport}
+					class="rounded-sm bg-primary px-5 py-2 font-sans text-xs font-bold tracking-widest text-primary-fg uppercase transition-opacity hover:opacity-80"
+				>
+					{m.admin_system_import_btn_retry()}
+				</button>
+			{:else if importStatus?.state === 'FAILED'}
+				<p class="mb-4 rounded-sm border border-red-200 bg-red-50 p-3 text-sm text-red-700">
+					{m.admin_system_import_status_failed({ message: importStatus.message })}
+				</p>
+				<button
+					data-import-trigger
+					onclick={triggerImport}
+					class="rounded-sm bg-primary px-5 py-2 font-sans text-xs font-bold tracking-widest text-primary-fg uppercase transition-opacity hover:opacity-80"
+				>
+					{m.admin_system_import_btn_retry()}
+				</button>
+			{:else}
+				{#if importStatus !== null}
+					<p class="mb-4 text-sm text-ink-2">{m.admin_system_import_status_idle()}</p>
+				{/if}
+				<button
+					data-import-trigger
+					onclick={triggerImport}
+					class="rounded-sm bg-primary px-5 py-2 font-sans text-xs font-bold tracking-widest text-primary-fg uppercase transition-opacity hover:opacity-80"
+				>
+					{m.admin_system_import_btn_start()}
+				</button>
+			{/if}
+		</div>
 	</div>
 </div>

frontend/src/routes/admin/system/page.svelte.spec.ts

@@ -1,9 +1,10 @@
-import { afterEach, describe, expect, it } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
 import Page from './+page.svelte';
 
 afterEach(cleanup);
+afterEach(() => vi.restoreAllMocks());
 
 describe('Admin system page', () => {
 	it('renders the backfill versions heading', async () => {
@@ -32,3 +33,104 @@ describe('Admin system page', () => {
 			.toBeInTheDocument();
 	});
 });
+
+describe('Admin system page — mass import card', () => {
+	beforeEach(() => {
+		vi.stubGlobal(
+			'fetch',
+			vi.fn().mockResolvedValue({
+				ok: true,
+				json: async () => ({
+					state: 'IDLE',
+					message: 'Kein Import gestartet.',
+					processed: 0,
+					startedAt: null
+				})
+			})
+		);
+	});
+
+	it('renders the mass import heading', async () => {
+		render(Page, {});
+		await expect.element(page.getByText(/Massenimport/i)).toBeInTheDocument();
+	});
+
+	it('renders the start import button when idle', async () => {
+		render(Page, {});
+		await expect.element(page.getByRole('button', { name: /Import starten/i })).toBeInTheDocument();
+	});
+
+	it('shows idle status text', async () => {
+		render(Page, {});
+		await expect.element(page.getByText(/Kein Import gestartet/i)).toBeInTheDocument();
+	});
+
+	it('disables the start button and shows running state after click', async () => {
+		const fetchMock = vi
+			.fn()
+			// initial status fetch → IDLE
+			.mockResolvedValueOnce({
+				ok: true,
+				json: async () => ({
+					state: 'IDLE',
+					message: 'Kein Import gestartet.',
+					processed: 0,
+					startedAt: null
+				})
+			})
+			// trigger POST → returns RUNNING immediately
+			.mockResolvedValueOnce({
+				ok: true,
+				json: async () => ({
+					state: 'RUNNING',
+					message: 'Import läuft...',
+					processed: 0,
+					startedAt: '2026-01-01T10:00:00'
+				})
+			});
+		vi.stubGlobal('fetch', fetchMock);
+
+		render(Page, {});
+		await expect.element(page.getByRole('button', { name: /Import starten/i })).toBeInTheDocument();
+
+		document.querySelector<HTMLButtonElement>('[data-import-trigger]')!.click();
+
+		await expect.element(page.getByText(/Import läuft/i)).toBeInTheDocument();
+	});
+
+	it('shows done status and retry button after successful import', async () => {
+		vi.stubGlobal(
+			'fetch',
+			vi.fn().mockResolvedValue({
+				ok: true,
+				json: async () => ({
+					state: 'DONE',
+					message: 'Import abgeschlossen.',
+					processed: 42,
+					startedAt: '2026-01-01T10:00:00'
+				})
+			})
+		);
+		render(Page, {});
+		await expect.element(page.getByText(/42 Dokumente/i)).toBeInTheDocument();
+		await expect.element(page.getByRole('button', { name: /Erneut starten/i })).toBeInTheDocument();
+	});
+
+	it('shows failed status and retry button on error', async () => {
+		vi.stubGlobal(
+			'fetch',
+			vi.fn().mockResolvedValue({
+				ok: true,
+				json: async () => ({
+					state: 'FAILED',
+					message: 'Datei nicht gefunden.',
+					processed: 0,
+					startedAt: '2026-01-01T10:00:00'
+				})
+			})
+		);
+		render(Page, {});
+		await expect.element(page.getByText(/Datei nicht gefunden/i)).toBeInTheDocument();
+		await expect.element(page.getByRole('button', { name: /Erneut starten/i })).toBeInTheDocument();
+	});
+});