fix(reader-dashboard): recentDocs items were always undefined for READ_ALL users

The server mapped DocumentSearchResult items as { document: Document }[]
but the API returns flat DocumentListItem[] — so i.document was always
undefined, crashing the reader homepage with a 500.

Fix the type + mapping in +page.server.ts, add createdAt/updatedAt to
DocumentListItem (needed by ReaderRecentDocs for relative-time display),
and update the component to accept DocumentListItem instead of Document.

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

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

@@ -3,15 +3,15 @@ import * as m from '$lib/paraglide/messages.js';
 import { relativeTimeDe } from '$lib/shared/relativeTime';
 import type { components } from '$lib/generated/api';
 
-type Document = components['schemas']['Document'];
+type DocumentListItem = components['schemas']['DocumentListItem'];
 
 interface Props {
-	documents: Document[];
+	documents: DocumentListItem[];
 }
 
 const { documents }: Props = $props();
 
-function isNew(doc: Document): boolean {
+function isNew(doc: DocumentListItem): boolean {
 	return new Date(doc.createdAt).getTime() === new Date(doc.updatedAt).getTime();
 }
 </script>