fix(web): keep delivery status monotonic after reconnect

web/src/store/chatStore.ts

@@ -38,6 +38,21 @@ function saveDraftsToStorage(drafts: Record<number, string>): void {
   }
 }
 
+function mergeDeliveryStatus(
+  incoming: DeliveryStatus | undefined,
+  existing: DeliveryStatus | undefined
+): DeliveryStatus | undefined {
+  const rank: Record<DeliveryStatus, number> = {
+    sending: 1,
+    sent: 2,
+    delivered: 3,
+    read: 4
+  };
+  const incomingRank = incoming ? rank[incoming] : 0;
+  const existingRank = existing ? rank[existing] : 0;
+  return incomingRank >= existingRank ? incoming : existing;
+}
+
 interface ChatState {
   chats: Chat[];
   activeChatId: number | null;
@@ -106,10 +121,16 @@ export const useChatStore = create<ChatState>((set, get) => ({
     const unreadCount = get().chats.find((c) => c.id === chatId)?.unread_count ?? 0;
     const messages = await getMessages(chatId);
     const sorted = [...messages].reverse();
+    const existingById = new Map((get().messagesByChat[chatId] ?? []).map((message) => [message.id, message]));
+    const normalized = sorted.map((message) => {
+      const existing = existingById.get(message.id);
+      const deliveryStatus = mergeDeliveryStatus(message.delivery_status, existing?.delivery_status);
+      return deliveryStatus ? { ...message, delivery_status: deliveryStatus } : message;
+    });
     set((state) => ({
       messagesByChat: {
         ...state.messagesByChat,
-        [chatId]: sorted
+        [chatId]: normalized
       },
       unreadBoundaryByChat: {
         ...state.unreadBoundaryByChat,
@@ -127,7 +148,7 @@ export const useChatStore = create<ChatState>((set, get) => ({
         chat.id === chatId ? { ...chat, unread_count: 0, unread_mentions_count: 0 } : chat
       )
     }));
-    const lastMessage = sorted[sorted.length - 1];
+    const lastMessage = normalized[normalized.length - 1];
     if (lastMessage) {
       void updateMessageStatus(chatId, lastMessage.id, "message_read");
     }