Remove wixos (WSL) configuration

WSL is no longer used. This removes:
- machines/wixos/ directory and configuration.nix
- nixos-wsl input from flake.nix
- nixosConfigurations.wixos output
- References to wixos in AGENTS.md and .goosehints

Implements bead: nixos-configs-2mk

machines/wixos/configuration.nix

@@ -1,56 +0,0 @@
-# Edit this configuration file to define what should be installed on
-# your system. Help is available in the configuration.nix(5) man page, on
-# https://search.nixos.org/options and in the NixOS manual (`nixos-help`).
-
-# NixOS-WSL specific options are documented on the NixOS-WSL repository:
-# https://github.com/nix-community/NixOS-WSL
-
-{ config, lib, pkgs, ... }:
-
-{
-  imports = [
-  ];
-
-  roles = {
-    audio.enable = true;
-    desktop = {
-      enable = true;
-      wayland = true;
-    };
-    nvidia = {
-      enable = true;
-      package = "latest";
-      graphics.extraPackages = with pkgs; [
-        mesa
-        libvdpau-va-gl
-        libva-vdpau-driver
-      ];
-    };
-    users.enable = true;
-  };
-
-  networking.hostName = "wixos";
-
-  wsl.enable = true;
-  wsl.defaultUser = "johno";
-  wsl.startMenuLaunchers = true;
-  wsl.useWindowsDriver = true;
-  wsl.wslConf.network.hostname = "wixos";
-  wsl.wslConf.user.default = "johno";
-
-  # WSL-specific environment variables for graphics
-  environment.sessionVariables = {
-    LD_LIBRARY_PATH = [
-      "/usr/lib/wsl/lib"
-      "/run/opengl-driver/lib"
-    ];
-  };
-
-  # This value determines the NixOS release from which the default
-  # settings for stateful data, like file locations and database versions
-  # on your system were taken. It's perfectly fine and recommended to leave
-  # this value at the release version of the first install of this system.
-  # Before changing this value read the documentation for this option
-  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
-  system.stateVersion = "24.05"; # Did you read the comment?
-}