新增 pc-client：畅联 PC 端工程（Electron+React，按确认效果图改造，B-59）

- 基于 openim-electron-demo 改造：工号+密码登录（自研账号服务）、会话列表/聊天窗/通讯录界面重做
- 文字/语音/文件/图片消息、文件拖拽发送、表情面板、一对一语音通话（LiveKit）
- RTC 令牌对接账号服务带鉴权版 /api/rtc_token（Bearer imToken + {room,identity}）
- account-service: CORS Allow-Headers 补 authorization（浏览器/渲染进程跨域调 rtc_token 需要）
- 附本地 mock 账号服务（scripts/mock-account-server.js）与截图联调脚本

pc-client/electron/utils/log.ts

@@ -0,0 +1,17 @@
+import log from "electron-log/main";
+import { join } from "node:path";
+import fs from "fs";
+
+const getLogger = (logsPath: string) => {
+  log.transports.file.level = "debug";
+  log.transports.file.maxSize = 104857600; // max size 100M
+  log.transports.file.format = "[{y}-{m}-{d} {h}:{i}:{s}.{ms}] [{level}]{scope} {text}";
+  let date = new Date();
+  // let dateStr = date.getFullYear() + "-" + (date.getMonth() + 1) + "-" + date.getDate();
+  // log.transports.file.resolvePathFn = () => join(logsPath, `log${dateStr}.log`);
+  log.transports.file.resolvePathFn = () => join(logsPath, `OpenIM.log`);
+  log.initialize({ preload: true });
+  return log.scope("ipcMain");
+};
+
+export { getLogger };