sam: Move channel 25.05 → nixos-unstable

This requires a corresponding home-manager move, above, and removes the requirement for a changed openconnect.

sam/configuration.nix

@@ -4,7 +4,7 @@
   imports =
     [
       ./hardware-configuration.nix
-      (import "${builtins.fetchTarball https://github.com/nix-community/home-manager/archive/release-25.05.tar.gz}/nixos")
+      (import "${builtins.fetchTarball https://github.com/nix-community/home-manager/archive/master.tar.gz}/nixos")
     ];
 
   # https://discourse.nixos.org/t/github-strategies-for-configuration-nix/1983/14
@@ -116,9 +116,7 @@
       jujutsu
       killall
       kubectl
-      # From https://github.com/NixOS/nixpkgs/pull/370555
-      # I don't expect this to be backported, so this should be removed with 25.11
-      (import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/a5ea75e611fb5bf6898d7d72401f6cb2aacf30f0.tar.gz") {}).openconnect
+      openconnect
       pv
       ripgrep
       unzip