perf: Socket 连接异步化，使用 requestIdleCallback 不阻塞首屏

- NotificationContext: 将 Socket 初始化包裹在 requestIdleCallback 中
- 设置 3 秒超时保护，确保连接不会被无限延迟
- 不支持 requestIdleCallback 的浏览器自动降级到 setTimeout(0)
- socket/index.js: 移除模块加载时的 console.log，减少首屏阻塞感知
- 所有页面的首屏渲染都不再被 Socket 连接阻塞

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/services/socket/index.js

@@ -10,25 +10,12 @@ import { socketService } from '../socketService';
 export const socket = socketService;
 export { socketService };
 
-// ⚡ 新增：暴露 Socket 实例到 window（用于调试和验证）
+// ⚡ 暴露 Socket 实例到 window（用于调试和验证）
+// 注意：移除首屏加载时的日志，避免阻塞感知
 if (typeof window !== 'undefined') {
     window.socket = socketService;
     window.socketService = socketService;
-
-    console.log(
-        '%c[Socket Service] ✅ Socket instance exposed to window',
-        'color: #4CAF50; font-weight: bold; font-size: 14px;'
-    );
-    console.log('  📍 window.socket:', window.socket);
-    console.log('  📍 window.socketService:', window.socketService);
-    console.log('  📍 Socket.IO instance:', window.socket?.socket);
-    console.log('  📍 Connection status:', window.socket?.connected ? '✅ Connected' : '❌ Disconnected');
+    // 日志已移除，如需调试可在控制台执行: console.log(window.socket)
 }
 
-// 打印当前使用的服务类型
-console.log(
-    '%c[Socket Service] Using REAL Socket Service',
-    'color: #4CAF50; font-weight: bold; font-size: 12px;'
-);
-
 export default socket;