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/+page.server.ts

@@ -0,0 +1,23 @@
+import { redirect } from '@sveltejs/kit';
+import { createApiClient } from '$lib/api.server';
+
+export async function load({
+	fetch,
+	locals
+}: {
+	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 api = createApiClient(fetch);
+	const result = await api.GET('/api/documents/incomplete');
+
+	const documents = result.response.ok ? (result.data ?? []) : [];
+
+	return { documents };
+}