fix: expose host GPU utilities to services

nix/module.nix

@@ -6,6 +6,10 @@ let
   cfg = config.services.nPanel;
 
   packageForSystem = self.packages.${pkgs.stdenv.hostPlatform.system}.default;
+  # GPU driver utilities belong to the active NixOS generation. They cannot be
+  # selected from nixpkgs here because they must match the host's configured
+  # NVIDIA driver.
+  hostRuntimeBin = "/run/current-system/sw/bin";
   toolPath = lib.makeBinPath [
     pkgs.bash
     pkgs.coreutils
@@ -94,7 +98,7 @@ EOF
     Group = "root";
     SupplementaryGroups = [ "docker" ];
     WorkingDirectory = "/var/lib/npanel";
-    Environment = [ "PATH=${toolPath}" ];
+    Environment = [ "PATH=${hostRuntimeBin}:${toolPath}" ];
 
     # The process sees fixed compatibility paths. Custom locations are bound
     # into that view; default locations need no self-bind mount.