feat(persons): enrich /persons list with stats bar, life dates, doc count chip

Load /api/stats in parallel; PersonsStatsBar shows totals; person cards
show alias, life date range, and document count badge.

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

frontend/src/routes/persons/PersonsStatsBar.svelte

@@ -0,0 +1,26 @@
+<script lang="ts">
+import { m } from '$lib/paraglide/messages.js';
+
+let {
+	totalPersons,
+	totalDocuments
+}: {
+	totalPersons: number;
+	totalDocuments: number;
+} = $props();
+
+const personsLabel = $derived(
+	totalPersons === 1
+		? m.persons_stats_persons_one()
+		: m.persons_stats_persons_many({ count: totalPersons })
+);
+const documentsLabel = $derived(
+	totalDocuments === 1
+		? m.persons_stats_documents_one()
+		: m.persons_stats_documents_many({ count: totalDocuments })
+);
+</script>
+
+<p class="font-sans text-sm text-ink-2">
+	{personsLabel} · {documentsLabel}
+</p>