gpui style hot reload demo project

[alanthinker]

I've created a project demonstrating how to hot-reload styles. I hope it's helpful.

https://github.com/alanthinker/gpui_style_hot_reload

After you run the program, modifying the styles.pjson file and saving, it will immediately apply the latest styles to the UI.

[alanthinker]

I've also developed a hot-reload layout feature. However, considering that controlling layouts via JSON is less flexible and more restrictive compared to using Rust code, this approach is better-suited for specific scenarios only.

Main features implemented:

• Hot reloading of layouts
• Data binding to top-level fields of an entity
• Connecting backend Rust events
• Embedding UI components written in Rust code into the pjson layout files

How to run:
(You must switch to the examples/layout_demo directory to run the example, as the file paths used are relative.)

cd examples/layout_demo
cargo run

Then modify either layout.pjson or styles.pjson, save the file, and observe the changes.