fix(message): improve message synchronization and reliability

Refactor the messaging subsystem to enhance data consistency, prevent race conditions during WebSocket reconnection, and ensure accurate unread counts.

- **WebSocket Reliability**: Implement `client_msg_id` for precise message ACK matching, preventing incorrect pending message resolution in high-frequency scenarios.
- **Sync Logic**: Update `WSMessageHandler` and `MessageManager` to use a bootstrapping state, ensuring buffered SSE events are flushed only after the initial synchronization is complete.
- **State Consistency**:
    - Introduce atomic unread count increments to prevent lost updates.
    - Implement conditional rollback for optimistic read receipts, ensuring that failed API calls do not overwrite newer, valid read states.
- **Resource Management**: Add reference counting to `useMessages` hook to prevent premature clearing of loading states during rapid conversation switching or React StrictMode double-invocations.
- **Data Integrity**: Update `UserCacheService` to re-read the latest message list before applying sender info enrichment, ensuring new messages arriving during the async process are correctly processed.

src/stores/message/store.ts

@@ -88,6 +88,10 @@ export interface MessageActions {
   removeMessage: (conversationId: string, messageId: string) => void;
   patchMessages: (conversationId: string, patches: Map<string, Partial<MessageResponse>>) => void;
   setUnreadCount: (total: number, system: number) => void;
+  /**
+   * 原子递增系统未读数：避免外部 RMW 造成丢失
+   */
+  incrementSystemUnreadAtomic: () => void;
   setLastSystemMessageAt: (time: string | null) => void;
   setSSEConnected: (connected: boolean) => void;
   setCurrentConversation: (conversationId: string | null) => void;
@@ -107,6 +111,16 @@ export interface MessageActions {
   ) => void;
   incrementUnreadAtomic: (conversationId: string) => void;
 
+  /**
+   * 原子回滚乐观已读：仅在当前会话的 my_last_read_seq 仍等于 expectedReadSeq 时才回滚
+   * 避免覆盖后续并发 markAsRead 已更新的更大值
+   */
+  rollbackReadIfUnchanged: (
+    conversationId: string,
+    expectedReadSeq: number,
+    prevUnreadCount: number,
+  ) => void;
+
   // 重置
   reset: () => void;
 }
@@ -393,6 +407,13 @@ export const useMessageStore = create<MessageStore>((set, get) => ({
     set({ totalUnreadCount: total, systemUnreadCount: system });
   },
 
+  incrementSystemUnreadAtomic: () => {
+    set(state => ({
+      totalUnreadCount: state.totalUnreadCount + 1,
+      systemUnreadCount: state.systemUnreadCount + 1,
+    }));
+  },
+
   setLastSystemMessageAt: (time: string | null) => {
     set({ lastSystemMessageAt: time });
     if (time) {
@@ -506,6 +527,36 @@ export const useMessageStore = create<MessageStore>((set, get) => ({
     });
   },
 
+  rollbackReadIfUnchanged: (
+    conversationId: string,
+    expectedReadSeq: number,
+    prevUnreadCount: number,
+  ) => {
+    const normalizedId = normalizeConversationId(conversationId);
+    set(state => {
+      const conversation = state.conversations.get(normalizedId);
+      if (!conversation) return state;
+      // 仅当本地乐观已读游标仍是本次写入的值时，才回滚未读
+      // 否则说明已被更新的 markAsRead 覆盖，不应回滚
+      if (Number(conversation.my_last_read_seq || 0) !== expectedReadSeq) {
+        return state;
+      }
+      const newConversations = new Map(state.conversations);
+      newConversations.set(normalizedId, {
+        ...conversation,
+        unread_count: prevUnreadCount,
+      });
+      const conversationList = sortConversationList(newConversations);
+      // 同步回滚 totalUnreadCount：加回本次扣减的未读数
+      const unreadDelta = prevUnreadCount - (conversation.unread_count || 0);
+      return {
+        conversations: newConversations,
+        conversationList,
+        totalUnreadCount: state.totalUnreadCount + unreadDelta,
+      };
+    });
+  },
+
   // ==================== 重置 ====================
 
   reset: () => {