Yet another permission denied

Recently wsld started failing on one of my machines with an obscure permission denied message. After fumbling with it for a while, I figured out that this is an issue of not being able to remove /tmp/.X11-unix/X0, and sudo-removing it made things good again.

Two things are relevant here:

1. I think that this has started recently because I did a new ubuntu setup -- and it now starts wslg as part of the setup, which means that you're left with a root-owned directory.
2. It would therefore be nice to revise the code a bit and say what exactly caused the error rather than a vague "permission denied" -- it would at least save me a couple of hours trying to run in random directions.

I think that the offending code is

https://github.com/nbdd0121/wsld/blob/c2247984e58de386a52e7f937f98a0d0712e627a/client/src/x11socket.rs#L66-L67

which looks like it's ignoring the prospect of not being able to write that, and fails in a generic way rather that just telling you what went wrong.

(This is probably a duplicate of a few other issues, and adding an error would mean not spending time telling people about removing the files :)

Start in client/src/x11socket.rs at lines 66-67, where the issue identifies the failure. Reproduce the X11 socket cleanup failure involving /tmp/.X11-unix/X0 and inspect how the error is surfaced. Done means the failure explains the specific operation or path instead of only reporting a generic permission-denied message.