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/playwright.config.ts

@@ -0,0 +1,54 @@
+import type { PlaywrightTestConfig } from "@playwright/test";
+
+/**
+ * Read environment variables from file.
+ * https://github.com/motdotla/dotenv
+ */
+// require('dotenv').config();
+
+/**
+ * See https://playwright.dev/docs/test-configuration.
+ */
+const config: PlaywrightTestConfig = {
+  testDir: "./e2e",
+  /* Maximum time one test can run for. */
+  timeout: 30 * 1000,
+  expect: {
+    /**
+     * Maximum time expect() should wait for the condition to be met.
+     * For example in `await expect(locator).toHaveText();`
+     */
+    timeout: 5000,
+  },
+  /* Run tests in files in parallel */
+  fullyParallel: true,
+  /* Fail the build on CI if you accidentally left test.only in the source code. */
+  forbidOnly: !!process.env.CI,
+  /* Retry on CI only */
+  retries: process.env.CI ? 2 : 0,
+  /* Opt out of parallel tests on CI. */
+  workers: process.env.CI ? 1 : undefined,
+  /* Reporter to use. See https://playwright.dev/docs/test-reporters */
+  reporter: "html",
+  /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
+  use: {
+    /* Maximum time each action such as `click()` can take. Defaults to 0 (no limit). */
+    actionTimeout: 0,
+    /* Base URL to use in actions like `await page.goto('/')`. */
+    // baseURL: 'http://localhost:3000',
+
+    /* Collect trace when retrying the failed test. See https://playwright.dev/docs/trace-viewer */
+    trace: "on-first-retry",
+  },
+
+  /* Folder for test artifacts such as screenshots, videos, traces, etc. */
+  // outputDir: 'test-results/',
+
+  /* Run your local dev server before starting the tests */
+  // webServer: {
+  //   command: 'npm run start',
+  //   port: 3000,
+  // },
+};
+
+export default config;