fix(weChat/ckchat): 修复切换联系人时未重置未读计数的问题

在切换联系人时，确保会话的未读计数被正确重置为0。将重置逻辑统一移至addChatSession方法中处理，避免遗漏。

Cunkebao/src/store/module/ckchat/ckchat.ts

@@ -9,7 +9,6 @@ import {
 } from "@/pages/pc/ckbox/data";
 import { kfUserService, weChatGroupService, contractService } from "@/utils/db";
 import { createContractList } from "@/store/module/ckchat/api";
-import { deepCopy } from "@/utils/common";
 
 export const useCkChatStore = createPersistStore<CkChatState>(
   set => ({
@@ -363,6 +362,7 @@ export const useCkChatStore = createPersistStore<CkChatState>(
     })(),
     // 添加聊天会话
     addChatSession: (session: ContractData | weChatGroup) => {
+      session.unreadCount = 0;
       set(state => {
         // 检查是否已存在相同id的会话
         const exists = state.chatSessions.some(item => item.id === session.id);

Cunkebao/src/store/module/weChat/weChat.ts

@@ -24,7 +24,6 @@ export const useWeChatStore = create<WeChatState>()(
         // 切换联系人时清空当前消息，等待重新加载
         set({ currentMessages: [] });
         clearUnreadCount([contract.id]).then(() => {
-          contract.unreadCount = 0;
           addChatSession(contract);
           set({ currentContract: contract });
           updateConfig({