Update README files to include migration notice to nativeapi

Author: lijy91

README-ZH.md

@@ -14,6 +14,8 @@
 
 这个插件为 Flutter 桌面应用程序提供了全面的窗口管理功能，使开发者能够完全控制窗口大小、位置、外观、关闭行为，以及监听事件。
 
+> 注意：本插件计划迁移至 [nativeapi](https://github.com/leanflutter/nativeapi-flutter) 以提升可维护性和性能，但目前该方案仍处于实验阶段。
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 [English](./README.md) | 简体中文

README.md

@@ -14,6 +14,8 @@
 
 This plugin provides comprehensive window management capabilities for Flutter desktop applications, enabling full control over window size, position, appearance, close behavior, and listening to events.
 
+> Note: This plugin is planned to migrate to [nativeapi](https://github.com/leanflutter/nativeapi-flutter) to improve maintainability and performance, but the solution is still experimental at this stage.
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 English | [简体中文](./README-ZH.md)