Add a virtual navigation bar 添加虚拟导航栏

操作全屏幕手势的手机很难进行返回、多任务等操作
Phones that operate full-screen gestures have a hard time doing things like going back, multitasking, and so on

因为我很喜欢在需要同时使用手机和电脑进行协助时使用scrcpy
Because I love using scrcpy when I need to use my phone and computer for assistance at the same time
但是每当我想返回时总是会调整窗口大小（我的电脑有触摸屏）
But the window is always resized whenever I want to go back (my computer has a touch screen)

有什么办法可以添加虚拟导航栏或者锁定窗口大小吗？
Is there any way to add a virtual navigation bar or lock the window size?

The issue names no files, tests, or entry points. First clarify whether the goal is an in-window virtual navigation bar, preventing touch gestures from resizing the scrcpy window, or both; then trace the Android control and desktop window-input paths. Done should include an agreed interaction design and verification that back and multitasking work without unwanted window resizing.