fix(timeline): show EventPill provenance even when the event has no date

The provenance token (abgeleitet/kuratiert) was nested inside the
{#if dateLabel} block, so an undated or UNKNOWN-precision event — e.g.
one in the undated bucket — rendered no provenance at all. Compose the
subtitle as an optional "{date} · " prefix in front of the always-present
provenance instead.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/timeline/EventPill.svelte

@@ -21,6 +21,9 @@ const dateLabel = $derived(timelineDateLabel(entry.eventDate, entry.precision, e
 const provenance = $derived(
 	entry.derived ? m.timeline_provenance_derived() : m.timeline_provenance_curated()
 );
+// Provenance always shows; the date is an optional prefix so an undated event
+// still reads "abgeleitet"/"kuratiert" (REQ-007).
+const subtitle = $derived(dateLabel ? `${dateLabel} · ${provenance}` : provenance);
 const canEdit = $derived(!entry.derived && entry.eventId != null);
 </script>
 
@@ -46,9 +49,7 @@ const canEdit = $derived(!entry.derived && entry.eventId != null);
 					>{entry.title}</span
 				>
 			{/if}
-			{#if dateLabel}
-				<span class="block font-sans text-xs text-ink-3">{dateLabel} · {provenance}</span>
-			{/if}
+			<span class="block font-sans text-xs text-ink-3">{subtitle}</span>
 		</span>
 		{#if canEdit}
 			<a