feat(frontend): restore session progress sidebar

app-instance/frontend/lib/chat-messages.ts

@@ -30,6 +30,42 @@ export function mergeServerWithPendingUsers(serverMessages: ChatMessage[], local
   return [...serverMessages, ...pendingUsers];
 }
 
+export function shouldMergePendingUsers(
+  serverMessages: ChatMessage[],
+  localMessages: ChatMessage[],
+  waitingForReply: boolean
+): boolean {
+  if (waitingForReply) {
+    return true;
+  }
+
+  const lastLocal = localMessages[localMessages.length - 1];
+  if (lastLocal?.role !== 'user') {
+    return false;
+  }
+
+  const counts = new Map<string, number>();
+  for (const message of serverMessages) {
+    const key = messageFingerprint(message);
+    counts.set(key, (counts.get(key) ?? 0) + 1);
+  }
+
+  for (const message of localMessages) {
+    if (message.role !== 'user') {
+      continue;
+    }
+    const key = messageFingerprint(message);
+    const count = counts.get(key) ?? 0;
+    if (count > 0) {
+      counts.set(key, count - 1);
+      continue;
+    }
+    return true;
+  }
+
+  return false;
+}
+
 export function getTaskCardMessageIndexes(messages: ChatMessage[]): Set<number> {
   const latestByTask = new Map<string, number>();