gpui: Support window resizing for `PlatformWindow` (zed-industries#27477

)

Support resizing windows to a specified size.

## macOS

https://github.com/user-attachments/assets/8c639bc2-ee5f-4adc-a850-576dac939574


## Wayland

[wayland.webm](https://github.com/user-attachments/assets/3d593604-83b4-488f-8f63-1cf4c0c0cb9a)

## X11

[x11.webm](https://github.com/user-attachments/assets/ce8fa62e-fb74-4641-abe8-70574011e630)

## Windows

https://github.com/user-attachments/assets/abb03e48-f82a-4d62-90b3-2598a4866c3f

Release Notes:

- N/A

gpui: Export raw_window_handle for wry to render WebView, and with a …

…WebView example.

Fix borrow_mut error on Windows.

Co-authored-by: Sunli <scott_s829@163.com>

gpui: Export raw_window_handle for wry to render WebView, and with a …

…WebView example.

Fix borrow_mut error on Windows.

Co-authored-by: Sunli <scott_s829@163.com>

gpui: Export raw_window_handle for wry to render WebView, and with a …

…WebView example.

Fix borrow_mut error on Windows.

Co-authored-by: Sunli <scott_s829@163.com>