For each LETTER entry, resolve the curated event whose documents set
contains the letter, in one batched pass over the events already loaded
(no per-letter query, no new column). The DTO gains a nullable
linkedEventId; non-letter entries keep null.

Refs #850

@@ -258,0 +279,4 @@
+        if (letterDocIds.isEmpty()) return Map.of();
+
+        Map<UUID, UUID> eventByDocId = new HashMap<>();
+        for (TimelineEvent ev : events) {

@@ -258,0 +284,4 @@
+            if (linkedDocs == null) continue;
+            for (Document linked : linkedDocs) {
+                if (letterDocIds.contains(linked.getId())) {
+                    eventByDocId.putIfAbsent(linked.getId(), ev.getId());

@@ -0,0 +42,4 @@
+// Event-as-header: a same-year curated event renders as this card's header, mirroring EventPill —
+// glyph + title + date · provenance + an edit pencil for a curator. The title is never repeated
+// as a separate floating pill (REQ-002).
+const accent = $derived(event ? getAccentConfig(event) : null);

@@ -0,0 +107,4 @@
+			class="flex items-center gap-2 border-b border-line px-3 py-2"
+		>
+			<span class="font-serif text-sm font-bold whitespace-pre-line text-ink">
+				<span aria-hidden="true">✉</span>

@@ -19,0 +35,4 @@
+// Inside an event card the year frames the time, and these archive titles already
+// embed the date — so the compact in-card letter drops the redundant date chip when a
+// title is present, halving the row height and killing the duplicate date (#850).
+const showDate = $derived(!compact || !entry.title);

@@ -42,0 +67,4 @@
+			// A curated event whose letters live in THIS band becomes the contained card's
+			// header — its title reads once, no separate pill (REQ-002). Otherwise it stays a
+			// plain pill/world-band (REQ-005).
+			const cluster = entry.eventId ? clusters.find((c) => c.eventId === entry.eventId) : undefined;

@@ -42,0 +74,4 @@
+			} else {
+				out.push({ t: 'event', entry });
+			}
+		} else if (loose.includes(entry)) {

@@ -42,0 +90,4 @@
+
+	// Cross-year clusters: a cluster whose event is NOT a same-year EVENT entry renders as a
+	// text-header card (no pill, no edit link) holding this year's linked letters (REQ-004).
+	for (const cluster of clusters) {

@@ -0,0 +32,4 @@
+	const lookup = new Map<string, string>();
+	const collect = (entries: TimelineEntryDTO[]) => {
+		for (const entry of entries) {
+			if (entry.kind === 'EVENT' && entry.eventId) lookup.set(entry.eventId, entry.title ?? '');

@@ -0,0 +36,4 @@
+		}
+	};
+	for (const band of timeline.years) collect(band.entries);
+	collect(timeline.undated);