fix: normalize workbench trace event page cursors

internal/cloud/server-workbench-http.ts

@@ -730,7 +730,7 @@ function turnSnapshot({ projection, result, session, trace }) {
 
 function traceEventPage(snapshot, options) {
   const sourceEvents = Array.isArray(snapshot?.events) ? snapshot.events : [];
-  const indexed = sourceEvents.map((event, index) => ({ event, seq: eventSeq(event, index) }));
+  const indexed = normalizedTracePageEvents(sourceEvents);
   const startIndex = indexed.findIndex((item) => item.seq > options.afterSeq);
   const offset = startIndex >= 0 ? startIndex : indexed.length;
   const page = indexed.slice(offset, offset + options.limit);
@@ -756,6 +756,39 @@ function traceEventPage(snapshot, options) {
   };
 }
 
+function normalizedTracePageEvents(sourceEvents) {
+  return sourceEvents
+    .map((event, index) => ({
+      event,
+      sourceIndex: index,
+      persistedSeq: eventSeq(event, index),
+      sourceSeq: positiveTraceInteger(event?.sourceSeq),
+      createdAtMs: traceEventTimestampMs(event)
+    }))
+    .sort(compareTracePageEvents)
+    .map((item, index) => ({ event: item.event, seq: index + 1 }));
+}
+
+function compareTracePageEvents(left, right) {
+  if (left.createdAtMs !== right.createdAtMs) return left.createdAtMs - right.createdAtMs;
+  if (left.sourceSeq !== right.sourceSeq) return left.sourceSeq - right.sourceSeq;
+  if (left.persistedSeq !== right.persistedSeq) return left.persistedSeq - right.persistedSeq;
+  return left.sourceIndex - right.sourceIndex;
+}
+
+function traceEventTimestampMs(event) {
+  for (const value of [event?.createdAt, event?.occurredAt, event?.timestamp, event?.appendedAt]) {
+    const parsed = Date.parse(String(value ?? ""));
+    if (Number.isFinite(parsed)) return parsed;
+  }
+  return Number.MAX_SAFE_INTEGER;
+}
+
+function positiveTraceInteger(value) {
+  const parsed = Number(value);
+  return Number.isFinite(parsed) && parsed > 0 ? Math.trunc(parsed) : Number.MAX_SAFE_INTEGER;
+}
+
 function tracePageOptions(url) {
   const cursor = textValue(url.searchParams.get("cursor"));
   const cursorSeq = cursor.startsWith("seq:") ? Number.parseInt(cursor.slice(4), 10) : NaN;