fixes https://github.com/zed-industries/zed/issues/9132

By setting the app id, window managers like `sway` can apply custom
configuration like `for_window [app_id="zed"] floating enable`.
Tested using `wlprop`/`hyprctl activewindow` for wayland, `xprop` for
x11.


Release Notes:

- Zed now sets the window app id / class, which can be used e.g. in
window managers like `sway`/`i3` to define custom rules