Bump downward proxy buffer sizes from 1333 to 4096 bytes
This makes a ton of applications work on my system that didn't before, e.g.: SDL2 applications, blender, iced applications. I'm using an nvidia gpu with the 565.57.01 proprietary drivers and niri 0.1.10.
I choose 4096 arbitrarily because it seems sufficently large and is a nice power of 2, was 1333 (and 999) used intentially to catch certain types of bugs or align things a certain way?
The majority of applications that don't work yet seem to be because of only check WAYLAND_DISPLAY and not WAYLAND_SOCKET. Getting a path for the socket seems a bit complex (afaik there's no way to give other processes permission for /proc/{pid}/fd/{fd} so we need to create a file in the XDG_RUNTIME_DIR, make sure it doesn't conflict with other instances, and the wayland-rs implementation does some trickery to avoid race conditions). While doing so I ran into multiple fixes that I now realize were by you to said applications