feat: release chat and mindspace UI updates

src/utils/message.ts

@@ -113,6 +113,26 @@ export function normalizeConversationMessages(messages: Message[]): Message[] {
   );
 }
 
+/**
+ * Merge an authoritative server conversation snapshot into the currently
+ * displayed messages without ever erasing what the user can already see.
+ *
+ * `UpdateConversation` snapshots arrive on every SSE (re)connect — which on
+ * mobile happens constantly via the page visibility cycle. A mid-turn snapshot
+ * can be shorter than the live view (e.g. assistant messages not yet flagged
+ * userVisible), so a blind replace would blank an active conversation even
+ * though the backend session is alive and persisted. We therefore treat the
+ * snapshot as authoritative for content/order but keep any locally-displayed
+ * messages the snapshot hasn't caught up to yet (optimistic / in-flight tail).
+ * The authoritative full reload on `Finish` corrects any drift afterwards.
+ */
+export function mergeConversationSnapshot(current: Message[], incoming: Message[]): Message[] {
+  if (incoming.length === 0) return current;
+  const incomingIds = new Set(incoming.map((message) => message.id).filter(Boolean));
+  const localOnly = current.filter((message) => message.id && !incomingIds.has(message.id));
+  return localOnly.length ? [...incoming, ...localOnly] : incoming;
+}
+
 export function getDisplayText(message: Message): string {
   if ('displayText' in message.metadata) {
     return message.metadata.displayText ?? '';