feat(enrich): add metadata enrichment queue UI

Home page shows "Needs metadata" card when incomplete documents exist.
/enrich list shows all incomplete documents; /enrich/[id] provides a
split PDF-preview + compact form view with Skip / Save / Save & reviewed
actions that auto-advance through the queue.

New document page gets Save vs Save & reviewed split. Edit page gets
"Mark for review" secondary button to push a document back into the queue.

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

frontend/src/routes/enrich/[id]/+page.server.ts

@@ -0,0 +1,109 @@
+import { error, redirect } from '@sveltejs/kit';
+import { env } from '$env/dynamic/private';
+import { createApiClient } from '$lib/api.server';
+import { getErrorMessage, parseBackendError } from '$lib/errors';
+
+export async function load({
+	params,
+	fetch,
+	locals
+}: {
+	params: { id: string };
+	fetch: typeof globalThis.fetch;
+	locals: App.Locals;
+}) {
+	const canWrite =
+		locals.user?.groups?.some((g: { permissions: string[] }) =>
+			g.permissions.includes('WRITE_ALL')
+		) ?? false;
+	if (!canWrite) throw redirect(303, '/');
+
+	const { id } = params;
+	const api = createApiClient(fetch);
+
+	const [docResult, countResult] = await Promise.all([
+		api.GET('/api/documents/{id}', { params: { path: { id } } }),
+		api.GET('/api/documents/incomplete-count')
+	]);
+
+	if (!docResult.response.ok) {
+		const code = (docResult.error as unknown as { code?: string })?.code;
+		throw error(docResult.response.status, getErrorMessage(code));
+	}
+
+	const incompleteCount = countResult.response.ok ? (countResult.data?.count ?? 0) : 0;
+
+	return {
+		document: docResult.data!,
+		incompleteCount
+	};
+}
+
+async function redirectToNext(id: string, fetch: typeof globalThis.fetch): Promise<never> {
+	const api = createApiClient(fetch);
+	const nextResult = await api.GET('/api/documents/incomplete/next', {
+		params: { query: { excludeId: id } }
+	});
+
+	if (nextResult.response.ok && nextResult.data) {
+		throw redirect(303, `/enrich/${nextResult.data.id}`);
+	}
+	throw redirect(303, '/enrich/done');
+}
+
+export const actions = {
+	skip: async ({ params, fetch }: { params: { id: string }; fetch: typeof globalThis.fetch }) => {
+		await redirectToNext(params.id, fetch);
+	},
+
+	save: async ({
+		params,
+		request,
+		fetch
+	}: {
+		params: { id: string };
+		request: Request;
+		fetch: typeof globalThis.fetch;
+	}) => {
+		const baseUrl = env.API_INTERNAL_URL || 'http://localhost:8080';
+		const formData = await request.formData();
+
+		const res = await fetch(`${baseUrl}/api/documents/${params.id}`, {
+			method: 'PUT',
+			body: formData
+		});
+
+		if (!res.ok) {
+			const backendError = await parseBackendError(res);
+			return { error: getErrorMessage(backendError?.code) };
+		}
+
+		await redirectToNext(params.id, fetch);
+	},
+
+	saveAndReview: async ({
+		params,
+		request,
+		fetch
+	}: {
+		params: { id: string };
+		request: Request;
+		fetch: typeof globalThis.fetch;
+	}) => {
+		const baseUrl = env.API_INTERNAL_URL || 'http://localhost:8080';
+		const formData = await request.formData();
+		formData.set('metadataComplete', 'true');
+
+		const res = await fetch(`${baseUrl}/api/documents/${params.id}`, {
+			method: 'PUT',
+			body: formData
+		});
+
+		if (!res.ok) {
+			const backendError = await parseBackendError(res);
+			return { error: getErrorMessage(backendError?.code) };
+		}
+
+		await redirectToNext(params.id, fetch);
+	}
+};