feat(#145): update home page server load for dashboard mode

- Add isDashboard flag (true when no search filters active)
- In dashboard mode: fetch mentions, incompleteDocs, recentDocs via
  Promise.allSettled so widget failures don't crash the page
- In search mode: skip widget fetches for performance
- Replace incomplete-count fetch with list fetch (derive count from
  list.length)
- Update enrich page to use IncompleteDocumentDTO (id + title only)

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

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

@@ -5,14 +5,6 @@ let { data } = $props();
 
 const documents = $derived(data.documents);
 const count = $derived(documents.length);
-
-function formatUploadDate(createdAt: string): string {
-	return new Intl.DateTimeFormat('de-DE', {
-		day: 'numeric',
-		month: 'long',
-		year: 'numeric'
-	}).format(new Date(createdAt));
-}
 </script>
 
 <div class="mx-auto max-w-4xl px-4 py-10">
@@ -85,10 +77,7 @@ function formatUploadDate(createdAt: string): string {
 								<p
 									class="font-serif text-lg font-medium text-ink decoration-accent decoration-2 underline-offset-4 group-hover:underline"
 								>
-									{doc.title || doc.originalFilename}
-								</p>
-								<p class="mt-1 font-sans text-xs text-ink-3">
-									{formatUploadDate(doc.createdAt)}
+									{doc.title}
 								</p>
 							</div>
 							<img